Merge branch 'develop'

356 files changed, 5696 insertions, 6709 deletions

diff --git a/packages/backend/src/server/api/2fa.ts b/packages/backend/src/server/api/2fa.ts
index 2a69e49c83..e1c226979a 100644
--- a/packages/backend/src/server/api/2fa.ts
+++ b/packages/backend/src/server/api/2fa.ts
@@ -1,5 +1,5 @@
-import * as crypto from 'crypto';
-import config from '@/config/index';
+import * as crypto from 'node:crypto';
+import config from '@/config/index.js';
 import * as jsrsasign from 'jsrsasign';
 
 const ECC_PRELUDE = Buffer.from([0x04]);
diff --git a/packages/backend/src/server/api/api-handler.ts b/packages/backend/src/server/api/api-handler.ts
index 362bbb0f57..f97c3dd397 100644
--- a/packages/backend/src/server/api/api-handler.ts
+++ b/packages/backend/src/server/api/api-handler.ts
@@ -1,11 +1,11 @@
-import * as Koa from 'koa';
+import Koa from 'koa';
 
-import { IEndpoint } from './endpoints';
-import authenticate, { AuthenticationError } from './authenticate';
-import call from './call';
-import { ApiError } from './error';
+import { IEndpoint } from './endpoints.js';
+import authenticate, { AuthenticationError } from './authenticate.js';
+import call from './call.js';
+import { ApiError } from './error.js';
 
-export default (endpoint: IEndpoint, ctx: Koa.Context) => new Promise((res) => {
+export default (endpoint: IEndpoint, ctx: Koa.Context) => new Promise<void>((res) => {
 	const body = ctx.request.body;
 
 	const reply = (x?: any, y?: ApiError) => {
diff --git a/packages/backend/src/server/api/authenticate.ts b/packages/backend/src/server/api/authenticate.ts
index 9e2f3eb743..7fdf14666e 100644
--- a/packages/backend/src/server/api/authenticate.ts
+++ b/packages/backend/src/server/api/authenticate.ts
@@ -1,7 +1,7 @@
-import isNativeToken from './common/is-native-token';
-import { User } from '@/models/entities/user';
-import { Users, AccessTokens, Apps } from '@/models/index';
-import { AccessToken } from '@/models/entities/access-token';
+import isNativeToken from './common/is-native-token.js';
+import { User } from '@/models/entities/user.js';
+import { Users, AccessTokens, Apps } from '@/models/index.js';
+import { AccessToken } from '@/models/entities/access-token.js';
 
 export class AuthenticationError extends Error {
 	constructor(message: string) {
diff --git a/packages/backend/src/server/api/call.ts b/packages/backend/src/server/api/call.ts
index 18143340ae..5c5ef66019 100644
--- a/packages/backend/src/server/api/call.ts
+++ b/packages/backend/src/server/api/call.ts
@@ -1,11 +1,11 @@
-import * as Koa from 'koa';
+import Koa from 'koa';
 import { performance } from 'perf_hooks';
-import { limiter } from './limiter';
-import { User } from '@/models/entities/user';
-import endpoints from './endpoints';
-import { ApiError } from './error';
-import { apiLogger } from './logger';
-import { AccessToken } from '@/models/entities/access-token';
+import { limiter } from './limiter.js';
+import { User } from '@/models/entities/user.js';
+import endpoints, { IEndpoint } from './endpoints.js';
+import { ApiError } from './error.js';
+import { apiLogger } from './logger.js';
+import { AccessToken } from '@/models/entities/access-token.js';
 
 const accessDenied = {
 	message: 'Access denied.',
@@ -67,7 +67,7 @@ export default async (endpoint: string, user: User | null | undefined, token: Ac
 
 	if (ep.meta.requireCredential && ep.meta.limit && !user!.isAdmin && !user!.isModerator) {
 		// Rate limit
-		await limiter(ep, user!).catch(e => {
+		await limiter(ep as IEndpoint & { meta: { limit: NonNullable<IEndpoint['meta']['limit']> } }, user!).catch(e => {
 			throw new ApiError({
 				message: 'Rate limit exceeded. Please try again later.',
 				code: 'RATE_LIMIT_EXCEEDED',
@@ -78,10 +78,10 @@ export default async (endpoint: string, user: User | null | undefined, token: Ac
 	}
 
 	// Cast non JSON input
-	if (ep.meta.requireFile && ep.meta.params) {
-		for (const k of Object.keys(ep.meta.params)) {
-			const param = ep.meta.params[k];
-			if (['Boolean', 'Number'].includes(param.validator.name) && typeof data[k] === 'string') {
+	if (ep.meta.requireFile && ep.params.properties) {
+		for (const k of Object.keys(ep.params.properties)) {
+			const param = ep.params.properties![k];
+			if (['boolean', 'number', 'integer'].includes(param.type ?? '') && typeof data[k] === 'string') {
 				try {
 					data[k] = JSON.parse(data[k]);
 				} catch (e) {
@@ -91,8 +91,8 @@ export default async (endpoint: string, user: User | null | undefined, token: Ac
 						id: '0b5f1631-7c1a-41a6-b399-cce335f34d85',
 					}, {
 						param: k,
-						reason: `cannot cast to ${param.validator.name}`,
-					})
+						reason: `cannot cast to ${param.type}`,
+					});
 				}
 			}
 		}
diff --git a/packages/backend/src/server/api/common/generate-block-query.ts b/packages/backend/src/server/api/common/generate-block-query.ts
index 4fd6184738..60db1e731b 100644
--- a/packages/backend/src/server/api/common/generate-block-query.ts
+++ b/packages/backend/src/server/api/common/generate-block-query.ts
@@ -1,5 +1,5 @@
-import { User } from '@/models/entities/user';
-import { Blockings } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { Blockings } from '@/models/index.js';
 import { Brackets, SelectQueryBuilder } from 'typeorm';
 
 // ここでいうBlockedは被Blockedの意
diff --git a/packages/backend/src/server/api/common/generate-channel-query.ts b/packages/backend/src/server/api/common/generate-channel-query.ts
index 80a0acf7f9..333bb73b86 100644
--- a/packages/backend/src/server/api/common/generate-channel-query.ts
+++ b/packages/backend/src/server/api/common/generate-channel-query.ts
@@ -1,5 +1,5 @@
-import { User } from '@/models/entities/user';
-import { ChannelFollowings } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { ChannelFollowings } from '@/models/index.js';
 import { Brackets, SelectQueryBuilder } from 'typeorm';
 
 export function generateChannelQuery(q: SelectQueryBuilder<any>, me?: { id: User['id'] } | null) {
diff --git a/packages/backend/src/server/api/common/generate-muted-instance-query.ts b/packages/backend/src/server/api/common/generate-muted-instance-query.ts
index dbc9fc98f1..72a6fec68f 100644
--- a/packages/backend/src/server/api/common/generate-muted-instance-query.ts
+++ b/packages/backend/src/server/api/common/generate-muted-instance-query.ts
@@ -1,6 +1,6 @@
-import { User } from '@/models/entities/user';
-import { id } from '@/models/id';
-import { UserProfiles } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { id } from '@/models/id.js';
+import { UserProfiles } from '@/models/index.js';
 import { SelectQueryBuilder, Brackets } from 'typeorm';
 
 function createMutesQuery(id: string) {
diff --git a/packages/backend/src/server/api/common/generate-muted-note-query.ts b/packages/backend/src/server/api/common/generate-muted-note-query.ts
index 0737842613..f544e334d3 100644
--- a/packages/backend/src/server/api/common/generate-muted-note-query.ts
+++ b/packages/backend/src/server/api/common/generate-muted-note-query.ts
@@ -1,5 +1,5 @@
-import { User } from '@/models/entities/user';
-import { MutedNotes } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { MutedNotes } from '@/models/index.js';
 import { SelectQueryBuilder } from 'typeorm';
 
 export function generateMutedNoteQuery(q: SelectQueryBuilder<any>, me: { id: User['id'] }) {
diff --git a/packages/backend/src/server/api/common/generate-muted-note-thread-query.ts b/packages/backend/src/server/api/common/generate-muted-note-thread-query.ts
index 7e2cbd498b..7263ea2e60 100644
--- a/packages/backend/src/server/api/common/generate-muted-note-thread-query.ts
+++ b/packages/backend/src/server/api/common/generate-muted-note-thread-query.ts
@@ -1,5 +1,5 @@
-import { User } from '@/models/entities/user';
-import { NoteThreadMutings } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { NoteThreadMutings } from '@/models/index.js';
 import { Brackets, SelectQueryBuilder } from 'typeorm';
 
 export function generateMutedNoteThreadQuery(q: SelectQueryBuilder<any>, me: { id: User['id'] }) {
diff --git a/packages/backend/src/server/api/common/generate-muted-user-query.ts b/packages/backend/src/server/api/common/generate-muted-user-query.ts
index 7e200b87ef..79cb3ff894 100644
--- a/packages/backend/src/server/api/common/generate-muted-user-query.ts
+++ b/packages/backend/src/server/api/common/generate-muted-user-query.ts
@@ -1,5 +1,5 @@
-import { User } from '@/models/entities/user';
-import { Mutings } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { Mutings } from '@/models/index.js';
 import { SelectQueryBuilder, Brackets } from 'typeorm';
 
 export function generateMutedUserQuery(q: SelectQueryBuilder<any>, me: { id: User['id'] }, exclude?: User) {
diff --git a/packages/backend/src/server/api/common/generate-native-user-token.ts b/packages/backend/src/server/api/common/generate-native-user-token.ts
index 1f791c57ce..5d8a4c5378 100644
--- a/packages/backend/src/server/api/common/generate-native-user-token.ts
+++ b/packages/backend/src/server/api/common/generate-native-user-token.ts
@@ -1,3 +1,3 @@
-import { secureRndstr } from '@/misc/secure-rndstr';
+import { secureRndstr } from '@/misc/secure-rndstr.js';
 
 export default () => secureRndstr(16, true);
diff --git a/packages/backend/src/server/api/common/generate-replies-query.ts b/packages/backend/src/server/api/common/generate-replies-query.ts
index 249064d589..301782eab9 100644
--- a/packages/backend/src/server/api/common/generate-replies-query.ts
+++ b/packages/backend/src/server/api/common/generate-replies-query.ts
@@ -1,4 +1,4 @@
-import { User } from '@/models/entities/user';
+import { User } from '@/models/entities/user.js';
 import { Brackets, SelectQueryBuilder } from 'typeorm';
 
 export function generateRepliesQuery(q: SelectQueryBuilder<any>, me?: Pick<User, 'id' | 'showTimelineReplies'> | null) {
@@ -10,7 +10,7 @@ export function generateRepliesQuery(q: SelectQueryBuilder<any>, me?: Pick<User,
 				.andWhere('note.replyUserId = note.userId');
 			}));
 		}));
-	} else if(!me.showTimelineReplies) {
+	} else if (!me.showTimelineReplies) {
 		q.andWhere(new Brackets(qb => { qb
 			.where(`note.replyId IS NULL`) // 返信ではない
 			.orWhere('note.replyUserId = :meId', { meId: me.id }) // 返信だけど自分のノートへの返信
diff --git a/packages/backend/src/server/api/common/generate-visibility-query.ts b/packages/backend/src/server/api/common/generate-visibility-query.ts
index 813e8b6c09..715982934c 100644
--- a/packages/backend/src/server/api/common/generate-visibility-query.ts
+++ b/packages/backend/src/server/api/common/generate-visibility-query.ts
@@ -1,5 +1,5 @@
-import { User } from '@/models/entities/user';
-import { Followings } from '@/models/index';
+import { User } from '@/models/entities/user.js';
+import { Followings } from '@/models/index.js';
 import { Brackets, SelectQueryBuilder } from 'typeorm';
 
 export function generateVisibilityQuery(q: SelectQueryBuilder<any>, me?: { id: User['id'] } | null) {
diff --git a/packages/backend/src/server/api/common/getters.ts b/packages/backend/src/server/api/common/getters.ts
index 4b2ee8f1da..c5a47876d0 100644
--- a/packages/backend/src/server/api/common/getters.ts
+++ b/packages/backend/src/server/api/common/getters.ts
@@ -1,7 +1,7 @@
-import { IdentifiableError } from '@/misc/identifiable-error';
-import { User } from '@/models/entities/user';
-import { Note } from '@/models/entities/note';
-import { Notes, Users } from '@/models/index';
+import { IdentifiableError } from '@/misc/identifiable-error.js';
+import { User } from '@/models/entities/user.js';
+import { Note } from '@/models/entities/note.js';
+import { Notes, Users } from '@/models/index.js';
 
 /**
  * Get note for API processing
diff --git a/packages/backend/src/server/api/common/inject-featured.ts b/packages/backend/src/server/api/common/inject-featured.ts
index 1dc13c83ef..b7dd8028b5 100644
--- a/packages/backend/src/server/api/common/inject-featured.ts
+++ b/packages/backend/src/server/api/common/inject-featured.ts
@@ -1,9 +1,9 @@
 import rndstr from 'rndstr';
-import { Note } from '@/models/entities/note';
-import { User } from '@/models/entities/user';
-import { Notes, UserProfiles, NoteReactions } from '@/models/index';
-import { generateMutedUserQuery } from './generate-muted-user-query';
-import { generateBlockedUserQuery } from './generate-block-query';
+import { Note } from '@/models/entities/note.js';
+import { User } from '@/models/entities/user.js';
+import { Notes, UserProfiles, NoteReactions } from '@/models/index.js';
+import { generateMutedUserQuery } from './generate-muted-user-query.js';
+import { generateBlockedUserQuery } from './generate-block-query.js';
 
 // TODO: リアクション、Renote、返信などをしたノートは除外する
 
diff --git a/packages/backend/src/server/api/common/inject-promo.ts b/packages/backend/src/server/api/common/inject-promo.ts
index 06a3841995..b467b7b70b 100644
--- a/packages/backend/src/server/api/common/inject-promo.ts
+++ b/packages/backend/src/server/api/common/inject-promo.ts
@@ -1,7 +1,7 @@
 import rndstr from 'rndstr';
-import { Note } from '@/models/entities/note';
-import { User } from '@/models/entities/user';
-import { PromoReads, PromoNotes, Notes, Users } from '@/models/index';
+import { Note } from '@/models/entities/note.js';
+import { User } from '@/models/entities/user.js';
+import { PromoReads, PromoNotes, Notes, Users } from '@/models/index.js';
 
 export async function injectPromo(timeline: Note[], user?: User | null) {
 	if (timeline.length < 5) return;
diff --git a/packages/backend/src/server/api/common/read-messaging-message.ts b/packages/backend/src/server/api/common/read-messaging-message.ts
index 928333e59c..b0ce54d370 100644
--- a/packages/backend/src/server/api/common/read-messaging-message.ts
+++ b/packages/backend/src/server/api/common/read-messaging-message.ts
@@ -1,17 +1,17 @@
-import { publishMainStream, publishGroupMessagingStream } from '@/services/stream';
-import { publishMessagingStream } from '@/services/stream';
-import { publishMessagingIndexStream } from '@/services/stream';
-import { User, IRemoteUser } from '@/models/entities/user';
-import { MessagingMessage } from '@/models/entities/messaging-message';
-import { MessagingMessages, UserGroupJoinings, Users } from '@/models/index';
+import { publishMainStream, publishGroupMessagingStream } from '@/services/stream.js';
+import { publishMessagingStream } from '@/services/stream.js';
+import { publishMessagingIndexStream } from '@/services/stream.js';
+import { User, IRemoteUser } from '@/models/entities/user.js';
+import { MessagingMessage } from '@/models/entities/messaging-message.js';
+import { MessagingMessages, UserGroupJoinings, Users } from '@/models/index.js';
 import { In } from 'typeorm';
-import { IdentifiableError } from '@/misc/identifiable-error';
-import { UserGroup } from '@/models/entities/user-group';
-import { toArray } from '@/prelude/array';
-import { renderReadActivity } from '@/remote/activitypub/renderer/read';
-import { renderActivity } from '@/remote/activitypub/renderer/index';
-import { deliver } from '@/queue/index';
-import orderedCollection from '@/remote/activitypub/renderer/ordered-collection';
+import { IdentifiableError } from '@/misc/identifiable-error.js';
+import { UserGroup } from '@/models/entities/user-group.js';
+import { toArray } from '@/prelude/array.js';
+import { renderReadActivity } from '@/remote/activitypub/renderer/read.js';
+import { renderActivity } from '@/remote/activitypub/renderer/index.js';
+import { deliver } from '@/queue/index.js';
+import orderedCollection from '@/remote/activitypub/renderer/ordered-collection.js';
 
 /**
  * Mark messages as read
diff --git a/packages/backend/src/server/api/common/read-notification.ts b/packages/backend/src/server/api/common/read-notification.ts
index 049a7feed6..1f575042a0 100644
--- a/packages/backend/src/server/api/common/read-notification.ts
+++ b/packages/backend/src/server/api/common/read-notification.ts
@@ -1,7 +1,7 @@
-import { publishMainStream } from '@/services/stream';
-import { User } from '@/models/entities/user';
-import { Notification } from '@/models/entities/notification';
-import { Notifications, Users } from '@/models/index';
+import { publishMainStream } from '@/services/stream.js';
+import { User } from '@/models/entities/user.js';
+import { Notification } from '@/models/entities/notification.js';
+import { Notifications, Users } from '@/models/index.js';
 import { In } from 'typeorm';
 
 export async function readNotification(
diff --git a/packages/backend/src/server/api/common/signin.ts b/packages/backend/src/server/api/common/signin.ts
index df986fc457..163f132a44 100644
--- a/packages/backend/src/server/api/common/signin.ts
+++ b/packages/backend/src/server/api/common/signin.ts
@@ -1,10 +1,10 @@
-import * as Koa from 'koa';
+import Koa from 'koa';
 
-import config from '@/config/index';
-import { ILocalUser } from '@/models/entities/user';
-import { Signins } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { publishMainStream } from '@/services/stream';
+import config from '@/config/index.js';
+import { ILocalUser } from '@/models/entities/user.js';
+import { Signins } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { publishMainStream } from '@/services/stream.js';
 
 export default function(ctx: Koa.Context, user: ILocalUser, redirect = false) {
 	if (redirect) {
diff --git a/packages/backend/src/server/api/common/signup.ts b/packages/backend/src/server/api/common/signup.ts
index f8db7e374e..7689e8233f 100644
--- a/packages/backend/src/server/api/common/signup.ts
+++ b/packages/backend/src/server/api/common/signup.ts
@@ -1,15 +1,15 @@
-import * as bcrypt from 'bcryptjs';
-import { generateKeyPair } from 'crypto';
-import generateUserToken from './generate-native-user-token';
-import { User } from '@/models/entities/user';
-import { Users, UsedUsernames } from '@/models/index';
-import { UserProfile } from '@/models/entities/user-profile';
+import bcrypt from 'bcryptjs';
+import { generateKeyPair } from 'node:crypto';
+import generateUserToken from './generate-native-user-token.js';
+import { User } from '@/models/entities/user.js';
+import { Users, UsedUsernames } from '@/models/index.js';
+import { UserProfile } from '@/models/entities/user-profile.js';
 import { getConnection } from 'typeorm';
-import { genId } from '@/misc/gen-id';
-import { toPunyNullable } from '@/misc/convert-host';
-import { UserKeypair } from '@/models/entities/user-keypair';
-import { usersChart } from '@/services/chart/index';
-import { UsedUsername } from '@/models/entities/used-username';
+import { genId } from '@/misc/gen-id.js';
+import { toPunyNullable } from '@/misc/convert-host.js';
+import { UserKeypair } from '@/models/entities/user-keypair.js';
+import { usersChart } from '@/services/chart/index.js';
+import { UsedUsername } from '@/models/entities/used-username.js';
 
 export async function signup(opts: {
 	username: User['username'];
@@ -21,13 +21,13 @@ export async function signup(opts: {
 	let hash = passwordHash;
 
 	// Validate username
-	if (!Users.validateLocalUsername.ok(username)) {
+	if (!Users.validateLocalUsername(username)) {
 		throw new Error('INVALID_USERNAME');
 	}
 
 	if (password != null && passwordHash == null) {
 		// Validate password
-		if (!Users.validatePassword.ok(password)) {
+		if (!Users.validatePassword(password)) {
 			throw new Error('INVALID_PASSWORD');
 		}
 
diff --git a/packages/backend/src/server/api/define.ts b/packages/backend/src/server/api/define.ts
index e0720e2adb..9094fcffc6 100644
--- a/packages/backend/src/server/api/define.ts
+++ b/packages/backend/src/server/api/define.ts
@@ -1,11 +1,10 @@
-import * as fs from 'fs';
-import { ILocalUser } from '@/models/entities/user';
-import { IEndpointMeta } from './endpoints';
-import { ApiError } from './error';
-import { SchemaType } from '@/misc/schema';
-import { AccessToken } from '@/models/entities/access-token';
-
-type NonOptional<T> = T extends undefined ? never : T;
+import * as fs from 'node:fs';
+import Ajv from 'ajv';
+import { ILocalUser } from '@/models/entities/user.js';
+import { IEndpointMeta } from './endpoints.js';
+import { ApiError } from './error.js';
+import { Schema, SchemaType } from '@/misc/schema.js';
+import { AccessToken } from '@/models/entities/access-token.js';
 
 type SimpleUserInfo = {
 	id: ILocalUser['id'];
@@ -18,24 +17,27 @@ type SimpleUserInfo = {
 	isAdmin: ILocalUser['isAdmin'];
 	isModerator: ILocalUser['isModerator'];
 	isSilenced: ILocalUser['isSilenced'];
-};
-
-type Params<T extends IEndpointMeta> = {
-	[P in keyof T['params']]: NonNullable<T['params']>[P]['transform'] extends () => any
-		? ReturnType<NonNullable<T['params']>[P]['transform']>
-		: NonNullable<T['params']>[P]['default'] extends null | number | string
-			? NonOptional<ReturnType<NonNullable<T['params']>[P]['validator']['get']>[0]>
-			: ReturnType<NonNullable<T['params']>[P]['validator']['get']>[0];
+	showTimelineReplies: ILocalUser['showTimelineReplies'];
 };
 
 export type Response = Record<string, any> | void;
 
-type executor<T extends IEndpointMeta> =
-	(params: Params<T>, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any, cleanup?: () => any) =>
+// TODO: paramsの型をT['params']のスキーマ定義から推論する
+type executor<T extends IEndpointMeta, Ps extends Schema> =
+	(params: SchemaType<Ps>, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any, cleanup?: () => any) =>
 		Promise<T['res'] extends undefined ? Response : SchemaType<NonNullable<T['res']>>>;
 
-export default function <T extends IEndpointMeta>(meta: T, cb: executor<T>)
+const ajv = new Ajv({
+	useDefaults: true,
+});
+
+ajv.addFormat('misskey:id', /^[a-z0-9]+$/);
+
+export default function <T extends IEndpointMeta, Ps extends Schema>(meta: T, paramDef: Ps, cb: executor<T, Ps>)
 		: (params: any, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any) => Promise<any> {
+
+	const validate = ajv.compile(paramDef);
+
 	return (params: any, user: T['requireCredential'] extends true ? SimpleUserInfo : SimpleUserInfo | null, token: AccessToken | null, file?: any) => {
 		function cleanup() {
 			fs.unlink(file.path, () => {});
@@ -47,42 +49,22 @@ export default function <T extends IEndpointMeta>(meta: T, cb: executor<T>)
 			id: '4267801e-70d1-416a-b011-4ee502885d8b',
 		}));
 
-		const [ps, pserr] = getParams(meta, params);
-		if (pserr) {
+		const valid = validate(params);
+		if (!valid) {
 			if (file) cleanup();
-			return Promise.reject(pserr);
-		}
-
-		return cb(ps, user, token, file, cleanup);
-	};
-}
 
-function getParams<T extends IEndpointMeta>(defs: T, params: any): [Params<T>, ApiError | null] {
-	if (defs.params == null) return [params, null];
-
-	const x: any = {};
-	let err: ApiError | null = null;
-	Object.entries(defs.params).some(([k, def]) => {
-		const [v, e] = def.validator.get(params[k]);
-		if (e) {
-			err = new ApiError({
+			const errors = validate.errors!;
+			const err = new ApiError({
 				message: 'Invalid param.',
 				code: 'INVALID_PARAM',
 				id: '3d81ceae-475f-4600-b2a8-2bc116157532',
 			}, {
-				param: k,
-				reason: e.message,
+				param: errors[0].schemaPath,
+				reason: errors[0].message,
 			});
-			return true;
-		} else {
-			if (v === undefined && Object.prototype.hasOwnProperty.call(def, 'default')) {
-				x[k] = def.default;
-			} else {
-				x[k] = v;
-			}
-			if (def.transform) x[k] = def.transform(x[k]);
-			return false;
+			return Promise.reject(err);
 		}
-	});
-	return [x, err];
+
+		return cb(params as SchemaType<Ps>, user, token, file, cleanup);
+	};
 }
diff --git a/packages/backend/src/server/api/endpoints.ts b/packages/backend/src/server/api/endpoints.ts
index bb4e972b8e..6b4eff0780 100644
--- a/packages/backend/src/server/api/endpoints.ts
+++ b/packages/backend/src/server/api/endpoints.ts
@@ -1,31 +1,618 @@
-import { fileURLToPath } from 'url';
-import { dirname } from 'path';
-import { Context } from 'cafy';
-import * as path from 'path';
-import * as glob from 'glob';
-import { Schema } from '@/misc/schema';
+import { Schema } from '@/misc/schema.js';
 
-//const _filename = fileURLToPath(import.meta.url);
-const _filename = __filename;
-const _dirname = dirname(_filename);
+import * as ep___admin_abuseUserReports from './endpoints/admin/abuse-user-reports.js';
+import * as ep___admin_accounts_create from './endpoints/admin/accounts/create.js';
+import * as ep___admin_accounts_delete from './endpoints/admin/accounts/delete.js';
+import * as ep___admin_ad_create from './endpoints/admin/ad/create.js';
+import * as ep___admin_ad_delete from './endpoints/admin/ad/delete.js';
+import * as ep___admin_ad_list from './endpoints/admin/ad/list.js';
+import * as ep___admin_ad_update from './endpoints/admin/ad/update.js';
+import * as ep___admin_announcements_create from './endpoints/admin/announcements/create.js';
+import * as ep___admin_announcements_delete from './endpoints/admin/announcements/delete.js';
+import * as ep___admin_announcements_list from './endpoints/admin/announcements/list.js';
+import * as ep___admin_announcements_update from './endpoints/admin/announcements/update.js';
+import * as ep___admin_deleteAllFilesOfAUser from './endpoints/admin/delete-all-files-of-a-user.js';
+import * as ep___admin_drive_cleanRemoteFiles from './endpoints/admin/drive/clean-remote-files.js';
+import * as ep___admin_drive_cleanup from './endpoints/admin/drive/cleanup.js';
+import * as ep___admin_drive_files from './endpoints/admin/drive/files.js';
+import * as ep___admin_drive_showFile from './endpoints/admin/drive/show-file.js';
+import * as ep___admin_emoji_addAliasesBulk from './endpoints/admin/emoji/add-aliases-bulk.js';
+import * as ep___admin_emoji_add from './endpoints/admin/emoji/add.js';
+import * as ep___admin_emoji_copy from './endpoints/admin/emoji/copy.js';
+import * as ep___admin_emoji_deleteBulk from './endpoints/admin/emoji/delete-bulk.js';
+import * as ep___admin_emoji_delete from './endpoints/admin/emoji/delete.js';
+import * as ep___admin_emoji_importZip from './endpoints/admin/emoji/import-zip.js';
+import * as ep___admin_emoji_listRemote from './endpoints/admin/emoji/list-remote.js';
+import * as ep___admin_emoji_list from './endpoints/admin/emoji/list.js';
+import * as ep___admin_emoji_removeAliasesBulk from './endpoints/admin/emoji/remove-aliases-bulk.js';
+import * as ep___admin_emoji_setAliasesBulk from './endpoints/admin/emoji/set-aliases-bulk.js';
+import * as ep___admin_emoji_setCategoryBulk from './endpoints/admin/emoji/set-category-bulk.js';
+import * as ep___admin_emoji_update from './endpoints/admin/emoji/update.js';
+import * as ep___admin_federation_deleteAllFiles from './endpoints/admin/federation/delete-all-files.js';
+import * as ep___admin_federation_refreshRemoteInstanceMetadata from './endpoints/admin/federation/refresh-remote-instance-metadata.js';
+import * as ep___admin_federation_removeAllFollowing from './endpoints/admin/federation/remove-all-following.js';
+import * as ep___admin_federation_updateInstance from './endpoints/admin/federation/update-instance.js';
+import * as ep___admin_getIndexStats from './endpoints/admin/get-index-stats.js';
+import * as ep___admin_getTableStats from './endpoints/admin/get-table-stats.js';
+import * as ep___admin_invite from './endpoints/admin/invite.js';
+import * as ep___admin_moderators_add from './endpoints/admin/moderators/add.js';
+import * as ep___admin_moderators_remove from './endpoints/admin/moderators/remove.js';
+import * as ep___admin_promo_create from './endpoints/admin/promo/create.js';
+import * as ep___admin_queue_clear from './endpoints/admin/queue/clear.js';
+import * as ep___admin_queue_deliverDelayed from './endpoints/admin/queue/deliver-delayed.js';
+import * as ep___admin_queue_inboxDelayed from './endpoints/admin/queue/inbox-delayed.js';
+import * as ep___admin_queue_stats from './endpoints/admin/queue/stats.js';
+import * as ep___admin_relays_add from './endpoints/admin/relays/add.js';
+import * as ep___admin_relays_list from './endpoints/admin/relays/list.js';
+import * as ep___admin_relays_remove from './endpoints/admin/relays/remove.js';
+import * as ep___admin_resetPassword from './endpoints/admin/reset-password.js';
+import * as ep___admin_resolveAbuseUserReport from './endpoints/admin/resolve-abuse-user-report.js';
+import * as ep___admin_sendEmail from './endpoints/admin/send-email.js';
+import * as ep___admin_serverInfo from './endpoints/admin/server-info.js';
+import * as ep___admin_showModerationLogs from './endpoints/admin/show-moderation-logs.js';
+import * as ep___admin_showUser from './endpoints/admin/show-user.js';
+import * as ep___admin_showUsers from './endpoints/admin/show-users.js';
+import * as ep___admin_silenceUser from './endpoints/admin/silence-user.js';
+import * as ep___admin_suspendUser from './endpoints/admin/suspend-user.js';
+import * as ep___admin_unsilenceUser from './endpoints/admin/unsilence-user.js';
+import * as ep___admin_unsuspendUser from './endpoints/admin/unsuspend-user.js';
+import * as ep___admin_updateMeta from './endpoints/admin/update-meta.js';
+import * as ep___admin_vacuum from './endpoints/admin/vacuum.js';
+import * as ep___announcements from './endpoints/announcements.js';
+import * as ep___antennas_create from './endpoints/antennas/create.js';
+import * as ep___antennas_delete from './endpoints/antennas/delete.js';
+import * as ep___antennas_list from './endpoints/antennas/list.js';
+import * as ep___antennas_notes from './endpoints/antennas/notes.js';
+import * as ep___antennas_show from './endpoints/antennas/show.js';
+import * as ep___antennas_update from './endpoints/antennas/update.js';
+import * as ep___ap_get from './endpoints/ap/get.js';
+import * as ep___ap_show from './endpoints/ap/show.js';
+import * as ep___app_create from './endpoints/app/create.js';
+import * as ep___app_show from './endpoints/app/show.js';
+import * as ep___auth_accept from './endpoints/auth/accept.js';
+import * as ep___auth_session_generate from './endpoints/auth/session/generate.js';
+import * as ep___auth_session_show from './endpoints/auth/session/show.js';
+import * as ep___auth_session_userkey from './endpoints/auth/session/userkey.js';
+import * as ep___blocking_create from './endpoints/blocking/create.js';
+import * as ep___blocking_delete from './endpoints/blocking/delete.js';
+import * as ep___blocking_list from './endpoints/blocking/list.js';
+import * as ep___channels_create from './endpoints/channels/create.js';
+import * as ep___channels_featured from './endpoints/channels/featured.js';
+import * as ep___channels_follow from './endpoints/channels/follow.js';
+import * as ep___channels_followed from './endpoints/channels/followed.js';
+import * as ep___channels_owned from './endpoints/channels/owned.js';
+import * as ep___channels_show from './endpoints/channels/show.js';
+import * as ep___channels_timeline from './endpoints/channels/timeline.js';
+import * as ep___channels_unfollow from './endpoints/channels/unfollow.js';
+import * as ep___channels_update from './endpoints/channels/update.js';
+import * as ep___charts_activeUsers from './endpoints/charts/active-users.js';
+import * as ep___charts_apRequest from './endpoints/charts/ap-request.js';
+import * as ep___charts_drive from './endpoints/charts/drive.js';
+import * as ep___charts_federation from './endpoints/charts/federation.js';
+import * as ep___charts_hashtag from './endpoints/charts/hashtag.js';
+import * as ep___charts_instance from './endpoints/charts/instance.js';
+import * as ep___charts_notes from './endpoints/charts/notes.js';
+import * as ep___charts_user_drive from './endpoints/charts/user/drive.js';
+import * as ep___charts_user_following from './endpoints/charts/user/following.js';
+import * as ep___charts_user_notes from './endpoints/charts/user/notes.js';
+import * as ep___charts_user_reactions from './endpoints/charts/user/reactions.js';
+import * as ep___charts_users from './endpoints/charts/users.js';
+import * as ep___clips_addNote from './endpoints/clips/add-note.js';
+import * as ep___clips_create from './endpoints/clips/create.js';
+import * as ep___clips_delete from './endpoints/clips/delete.js';
+import * as ep___clips_list from './endpoints/clips/list.js';
+import * as ep___clips_notes from './endpoints/clips/notes.js';
+import * as ep___clips_show from './endpoints/clips/show.js';
+import * as ep___clips_update from './endpoints/clips/update.js';
+import * as ep___drive from './endpoints/drive.js';
+import * as ep___drive_files from './endpoints/drive/files.js';
+import * as ep___drive_files_attachedNotes from './endpoints/drive/files/attached-notes.js';
+import * as ep___drive_files_checkExistence from './endpoints/drive/files/check-existence.js';
+import * as ep___drive_files_create from './endpoints/drive/files/create.js';
+import * as ep___drive_files_delete from './endpoints/drive/files/delete.js';
+import * as ep___drive_files_findByHash from './endpoints/drive/files/find-by-hash.js';
+import * as ep___drive_files_find from './endpoints/drive/files/find.js';
+import * as ep___drive_files_show from './endpoints/drive/files/show.js';
+import * as ep___drive_files_update from './endpoints/drive/files/update.js';
+import * as ep___drive_files_uploadFromUrl from './endpoints/drive/files/upload-from-url.js';
+import * as ep___drive_folders from './endpoints/drive/folders.js';
+import * as ep___drive_folders_create from './endpoints/drive/folders/create.js';
+import * as ep___drive_folders_delete from './endpoints/drive/folders/delete.js';
+import * as ep___drive_folders_find from './endpoints/drive/folders/find.js';
+import * as ep___drive_folders_show from './endpoints/drive/folders/show.js';
+import * as ep___drive_folders_update from './endpoints/drive/folders/update.js';
+import * as ep___drive_stream from './endpoints/drive/stream.js';
+import * as ep___emailAddress_available from './endpoints/email-address/available.js';
+import * as ep___endpoint from './endpoints/endpoint.js';
+import * as ep___endpoints from './endpoints/endpoints.js';
+import * as ep___exportCustomEmojis from './endpoints/export-custom-emojis.js';
+import * as ep___federation_followers from './endpoints/federation/followers.js';
+import * as ep___federation_following from './endpoints/federation/following.js';
+import * as ep___federation_instances from './endpoints/federation/instances.js';
+import * as ep___federation_showInstance from './endpoints/federation/show-instance.js';
+import * as ep___federation_updateRemoteUser from './endpoints/federation/update-remote-user.js';
+import * as ep___federation_users from './endpoints/federation/users.js';
+import * as ep___following_create from './endpoints/following/create.js';
+import * as ep___following_delete from './endpoints/following/delete.js';
+import * as ep___following_invalidate from './endpoints/following/invalidate.js';
+import * as ep___following_requests_accept from './endpoints/following/requests/accept.js';
+import * as ep___following_requests_cancel from './endpoints/following/requests/cancel.js';
+import * as ep___following_requests_list from './endpoints/following/requests/list.js';
+import * as ep___following_requests_reject from './endpoints/following/requests/reject.js';
+import * as ep___gallery_featured from './endpoints/gallery/featured.js';
+import * as ep___gallery_popular from './endpoints/gallery/popular.js';
+import * as ep___gallery_posts from './endpoints/gallery/posts.js';
+import * as ep___gallery_posts_create from './endpoints/gallery/posts/create.js';
+import * as ep___gallery_posts_delete from './endpoints/gallery/posts/delete.js';
+import * as ep___gallery_posts_like from './endpoints/gallery/posts/like.js';
+import * as ep___gallery_posts_show from './endpoints/gallery/posts/show.js';
+import * as ep___gallery_posts_unlike from './endpoints/gallery/posts/unlike.js';
+import * as ep___gallery_posts_update from './endpoints/gallery/posts/update.js';
+import * as ep___getOnlineUsersCount from './endpoints/get-online-users-count.js';
+import * as ep___hashtags_list from './endpoints/hashtags/list.js';
+import * as ep___hashtags_search from './endpoints/hashtags/search.js';
+import * as ep___hashtags_show from './endpoints/hashtags/show.js';
+import * as ep___hashtags_trend from './endpoints/hashtags/trend.js';
+import * as ep___hashtags_users from './endpoints/hashtags/users.js';
+import * as ep___i from './endpoints/i.js';
+import * as ep___i_2fa_done from './endpoints/i/2fa/done.js';
+import * as ep___i_2fa_keyDone from './endpoints/i/2fa/key-done.js';
+import * as ep___i_2fa_passwordLess from './endpoints/i/2fa/password-less.js';
+import * as ep___i_2fa_registerKey from './endpoints/i/2fa/register-key.js';
+import * as ep___i_2fa_register from './endpoints/i/2fa/register.js';
+import * as ep___i_2fa_removeKey from './endpoints/i/2fa/remove-key.js';
+import * as ep___i_2fa_unregister from './endpoints/i/2fa/unregister.js';
+import * as ep___i_apps from './endpoints/i/apps.js';
+import * as ep___i_authorizedApps from './endpoints/i/authorized-apps.js';
+import * as ep___i_changePassword from './endpoints/i/change-password.js';
+import * as ep___i_deleteAccount from './endpoints/i/delete-account.js';
+import * as ep___i_exportBlocking from './endpoints/i/export-blocking.js';
+import * as ep___i_exportFollowing from './endpoints/i/export-following.js';
+import * as ep___i_exportMute from './endpoints/i/export-mute.js';
+import * as ep___i_exportNotes from './endpoints/i/export-notes.js';
+import * as ep___i_exportUserLists from './endpoints/i/export-user-lists.js';
+import * as ep___i_favorites from './endpoints/i/favorites.js';
+import * as ep___i_gallery_likes from './endpoints/i/gallery/likes.js';
+import * as ep___i_gallery_posts from './endpoints/i/gallery/posts.js';
+import * as ep___i_getWordMutedNotesCount from './endpoints/i/get-word-muted-notes-count.js';
+import * as ep___i_importBlocking from './endpoints/i/import-blocking.js';
+import * as ep___i_importFollowing from './endpoints/i/import-following.js';
+import * as ep___i_importMuting from './endpoints/i/import-muting.js';
+import * as ep___i_importUserLists from './endpoints/i/import-user-lists.js';
+import * as ep___i_notifications from './endpoints/i/notifications.js';
+import * as ep___i_pageLikes from './endpoints/i/page-likes.js';
+import * as ep___i_pages from './endpoints/i/pages.js';
+import * as ep___i_pin from './endpoints/i/pin.js';
+import * as ep___i_readAllMessagingMessages from './endpoints/i/read-all-messaging-messages.js';
+import * as ep___i_readAllUnreadNotes from './endpoints/i/read-all-unread-notes.js';
+import * as ep___i_readAnnouncement from './endpoints/i/read-announcement.js';
+import * as ep___i_regenerateToken from './endpoints/i/regenerate-token.js';
+import * as ep___i_registry_getAll from './endpoints/i/registry/get-all.js';
+import * as ep___i_registry_getDetail from './endpoints/i/registry/get-detail.js';
+import * as ep___i_registry_get from './endpoints/i/registry/get.js';
+import * as ep___i_registry_keysWithType from './endpoints/i/registry/keys-with-type.js';
+import * as ep___i_registry_keys from './endpoints/i/registry/keys.js';
+import * as ep___i_registry_remove from './endpoints/i/registry/remove.js';
+import * as ep___i_registry_scopes from './endpoints/i/registry/scopes.js';
+import * as ep___i_registry_set from './endpoints/i/registry/set.js';
+import * as ep___i_revokeToken from './endpoints/i/revoke-token.js';
+import * as ep___i_signinHistory from './endpoints/i/signin-history.js';
+import * as ep___i_unpin from './endpoints/i/unpin.js';
+import * as ep___i_updateEmail from './endpoints/i/update-email.js';
+import * as ep___i_update from './endpoints/i/update.js';
+import * as ep___i_userGroupInvites from './endpoints/i/user-group-invites.js';
+import * as ep___messaging_history from './endpoints/messaging/history.js';
+import * as ep___messaging_messages from './endpoints/messaging/messages.js';
+import * as ep___messaging_messages_create from './endpoints/messaging/messages/create.js';
+import * as ep___messaging_messages_delete from './endpoints/messaging/messages/delete.js';
+import * as ep___messaging_messages_read from './endpoints/messaging/messages/read.js';
+import * as ep___meta from './endpoints/meta.js';
+import * as ep___miauth_genToken from './endpoints/miauth/gen-token.js';
+import * as ep___mute_create from './endpoints/mute/create.js';
+import * as ep___mute_delete from './endpoints/mute/delete.js';
+import * as ep___mute_list from './endpoints/mute/list.js';
+import * as ep___my_apps from './endpoints/my/apps.js';
+import * as ep___notes from './endpoints/notes.js';
+import * as ep___notes_children from './endpoints/notes/children.js';
+import * as ep___notes_clips from './endpoints/notes/clips.js';
+import * as ep___notes_conversation from './endpoints/notes/conversation.js';
+import * as ep___notes_create from './endpoints/notes/create.js';
+import * as ep___notes_delete from './endpoints/notes/delete.js';
+import * as ep___notes_favorites_create from './endpoints/notes/favorites/create.js';
+import * as ep___notes_favorites_delete from './endpoints/notes/favorites/delete.js';
+import * as ep___notes_featured from './endpoints/notes/featured.js';
+import * as ep___notes_globalTimeline from './endpoints/notes/global-timeline.js';
+import * as ep___notes_hybridTimeline from './endpoints/notes/hybrid-timeline.js';
+import * as ep___notes_localTimeline from './endpoints/notes/local-timeline.js';
+import * as ep___notes_mentions from './endpoints/notes/mentions.js';
+import * as ep___notes_polls_recommendation from './endpoints/notes/polls/recommendation.js';
+import * as ep___notes_polls_vote from './endpoints/notes/polls/vote.js';
+import * as ep___notes_reactions from './endpoints/notes/reactions.js';
+import * as ep___notes_reactions_create from './endpoints/notes/reactions/create.js';
+import * as ep___notes_reactions_delete from './endpoints/notes/reactions/delete.js';
+import * as ep___notes_renotes from './endpoints/notes/renotes.js';
+import * as ep___notes_replies from './endpoints/notes/replies.js';
+import * as ep___notes_searchByTag from './endpoints/notes/search-by-tag.js';
+import * as ep___notes_search from './endpoints/notes/search.js';
+import * as ep___notes_show from './endpoints/notes/show.js';
+import * as ep___notes_state from './endpoints/notes/state.js';
+import * as ep___notes_threadMuting_create from './endpoints/notes/thread-muting/create.js';
+import * as ep___notes_threadMuting_delete from './endpoints/notes/thread-muting/delete.js';
+import * as ep___notes_timeline from './endpoints/notes/timeline.js';
+import * as ep___notes_translate from './endpoints/notes/translate.js';
+import * as ep___notes_unrenote from './endpoints/notes/unrenote.js';
+import * as ep___notes_userListTimeline from './endpoints/notes/user-list-timeline.js';
+import * as ep___notes_watching_create from './endpoints/notes/watching/create.js';
+import * as ep___notes_watching_delete from './endpoints/notes/watching/delete.js';
+import * as ep___notifications_create from './endpoints/notifications/create.js';
+import * as ep___notifications_markAllAsRead from './endpoints/notifications/mark-all-as-read.js';
+import * as ep___notifications_read from './endpoints/notifications/read.js';
+import * as ep___pagePush from './endpoints/page-push.js';
+import * as ep___pages_create from './endpoints/pages/create.js';
+import * as ep___pages_delete from './endpoints/pages/delete.js';
+import * as ep___pages_featured from './endpoints/pages/featured.js';
+import * as ep___pages_like from './endpoints/pages/like.js';
+import * as ep___pages_show from './endpoints/pages/show.js';
+import * as ep___pages_unlike from './endpoints/pages/unlike.js';
+import * as ep___pages_update from './endpoints/pages/update.js';
+import * as ep___ping from './endpoints/ping.js';
+import * as ep___pinnedUsers from './endpoints/pinned-users.js';
+import * as ep___promo_read from './endpoints/promo/read.js';
+import * as ep___requestResetPassword from './endpoints/request-reset-password.js';
+import * as ep___resetDb from './endpoints/reset-db.js';
+import * as ep___resetPassword from './endpoints/reset-password.js';
+import * as ep___serverInfo from './endpoints/server-info.js';
+import * as ep___stats from './endpoints/stats.js';
+import * as ep___sw_register from './endpoints/sw/register.js';
+import * as ep___sw_unregister from './endpoints/sw/unregister.js';
+import * as ep___test from './endpoints/test.js';
+import * as ep___username_available from './endpoints/username/available.js';
+import * as ep___users from './endpoints/users.js';
+import * as ep___users_clips from './endpoints/users/clips.js';
+import * as ep___users_followers from './endpoints/users/followers.js';
+import * as ep___users_following from './endpoints/users/following.js';
+import * as ep___users_gallery_posts from './endpoints/users/gallery/posts.js';
+import * as ep___users_getFrequentlyRepliedUsers from './endpoints/users/get-frequently-replied-users.js';
+import * as ep___users_groups_create from './endpoints/users/groups/create.js';
+import * as ep___users_groups_delete from './endpoints/users/groups/delete.js';
+import * as ep___users_groups_invitations_accept from './endpoints/users/groups/invitations/accept.js';
+import * as ep___users_groups_invitations_reject from './endpoints/users/groups/invitations/reject.js';
+import * as ep___users_groups_invite from './endpoints/users/groups/invite.js';
+import * as ep___users_groups_joined from './endpoints/users/groups/joined.js';
+import * as ep___users_groups_leave from './endpoints/users/groups/leave.js';
+import * as ep___users_groups_owned from './endpoints/users/groups/owned.js';
+import * as ep___users_groups_pull from './endpoints/users/groups/pull.js';
+import * as ep___users_groups_show from './endpoints/users/groups/show.js';
+import * as ep___users_groups_transfer from './endpoints/users/groups/transfer.js';
+import * as ep___users_groups_update from './endpoints/users/groups/update.js';
+import * as ep___users_lists_create from './endpoints/users/lists/create.js';
+import * as ep___users_lists_delete from './endpoints/users/lists/delete.js';
+import * as ep___users_lists_list from './endpoints/users/lists/list.js';
+import * as ep___users_lists_pull from './endpoints/users/lists/pull.js';
+import * as ep___users_lists_push from './endpoints/users/lists/push.js';
+import * as ep___users_lists_show from './endpoints/users/lists/show.js';
+import * as ep___users_lists_update from './endpoints/users/lists/update.js';
+import * as ep___users_notes from './endpoints/users/notes.js';
+import * as ep___users_pages from './endpoints/users/pages.js';
+import * as ep___users_reactions from './endpoints/users/reactions.js';
+import * as ep___users_recommendation from './endpoints/users/recommendation.js';
+import * as ep___users_relation from './endpoints/users/relation.js';
+import * as ep___users_reportAbuse from './endpoints/users/report-abuse.js';
+import * as ep___users_searchByUsernameAndHost from './endpoints/users/search-by-username-and-host.js';
+import * as ep___users_search from './endpoints/users/search.js';
+import * as ep___users_show from './endpoints/users/show.js';
+import * as ep___users_stats from './endpoints/users/stats.js';
 
-export type Param = {
-	validator: Context<any>;
-	transform?: any;
-	default?: any;
-	deprecated?: boolean;
-	ref?: string;
-};
+const eps = [
+	['admin/abuse-user-reports', ep___admin_abuseUserReports],
+	['admin/accounts/create', ep___admin_accounts_create],
+	['admin/accounts/delete', ep___admin_accounts_delete],
+	['admin/ad/create', ep___admin_ad_create],
+	['admin/ad/delete', ep___admin_ad_delete],
+	['admin/ad/list', ep___admin_ad_list],
+	['admin/ad/update', ep___admin_ad_update],
+	['admin/announcements/create', ep___admin_announcements_create],
+	['admin/announcements/delete', ep___admin_announcements_delete],
+	['admin/announcements/list', ep___admin_announcements_list],
+	['admin/announcements/update', ep___admin_announcements_update],
+	['admin/delete-all-files-of-a-user', ep___admin_deleteAllFilesOfAUser],
+	['admin/drive/clean-remote-files', ep___admin_drive_cleanRemoteFiles],
+	['admin/drive/cleanup', ep___admin_drive_cleanup],
+	['admin/drive/files', ep___admin_drive_files],
+	['admin/drive/show-file', ep___admin_drive_showFile],
+	['admin/emoji/add-aliases-bulk', ep___admin_emoji_addAliasesBulk],
+	['admin/emoji/add', ep___admin_emoji_add],
+	['admin/emoji/copy', ep___admin_emoji_copy],
+	['admin/emoji/delete-bulk', ep___admin_emoji_deleteBulk],
+	['admin/emoji/delete', ep___admin_emoji_delete],
+	['admin/emoji/import-zip', ep___admin_emoji_importZip],
+	['admin/emoji/list-remote', ep___admin_emoji_listRemote],
+	['admin/emoji/list', ep___admin_emoji_list],
+	['admin/emoji/remove-aliases-bulk', ep___admin_emoji_removeAliasesBulk],
+	['admin/emoji/set-aliases-bulk', ep___admin_emoji_setAliasesBulk],
+	['admin/emoji/set-category-bulk', ep___admin_emoji_setCategoryBulk],
+	['admin/emoji/update', ep___admin_emoji_update],
+	['admin/federation/delete-all-files', ep___admin_federation_deleteAllFiles],
+	['admin/federation/refresh-remote-instance-metadata', ep___admin_federation_refreshRemoteInstanceMetadata],
+	['admin/federation/remove-all-following', ep___admin_federation_removeAllFollowing],
+	['admin/federation/update-instance', ep___admin_federation_updateInstance],
+	['admin/get-index-stats', ep___admin_getIndexStats],
+	['admin/get-table-stats', ep___admin_getTableStats],
+	['admin/invite', ep___admin_invite],
+	['admin/moderators/add', ep___admin_moderators_add],
+	['admin/moderators/remove', ep___admin_moderators_remove],
+	['admin/promo/create', ep___admin_promo_create],
+	['admin/queue/clear', ep___admin_queue_clear],
+	['admin/queue/deliver-delayed', ep___admin_queue_deliverDelayed],
+	['admin/queue/inbox-delayed', ep___admin_queue_inboxDelayed],
+	['admin/queue/stats', ep___admin_queue_stats],
+	['admin/relays/add', ep___admin_relays_add],
+	['admin/relays/list', ep___admin_relays_list],
+	['admin/relays/remove', ep___admin_relays_remove],
+	['admin/reset-password', ep___admin_resetPassword],
+	['admin/resolve-abuse-user-report', ep___admin_resolveAbuseUserReport],
+	['admin/send-email', ep___admin_sendEmail],
+	['admin/server-info', ep___admin_serverInfo],
+	['admin/show-moderation-logs', ep___admin_showModerationLogs],
+	['admin/show-user', ep___admin_showUser],
+	['admin/show-users', ep___admin_showUsers],
+	['admin/silence-user', ep___admin_silenceUser],
+	['admin/suspend-user', ep___admin_suspendUser],
+	['admin/unsilence-user', ep___admin_unsilenceUser],
+	['admin/unsuspend-user', ep___admin_unsuspendUser],
+	['admin/update-meta', ep___admin_updateMeta],
+	['admin/vacuum', ep___admin_vacuum],
+	['announcements', ep___announcements],
+	['antennas/create', ep___antennas_create],
+	['antennas/delete', ep___antennas_delete],
+	['antennas/list', ep___antennas_list],
+	['antennas/notes', ep___antennas_notes],
+	['antennas/show', ep___antennas_show],
+	['antennas/update', ep___antennas_update],
+	['ap/get', ep___ap_get],
+	['ap/show', ep___ap_show],
+	['app/create', ep___app_create],
+	['app/show', ep___app_show],
+	['auth/accept', ep___auth_accept],
+	['auth/session/generate', ep___auth_session_generate],
+	['auth/session/show', ep___auth_session_show],
+	['auth/session/userkey', ep___auth_session_userkey],
+	['blocking/create', ep___blocking_create],
+	['blocking/delete', ep___blocking_delete],
+	['blocking/list', ep___blocking_list],
+	['channels/create', ep___channels_create],
+	['channels/featured', ep___channels_featured],
+	['channels/follow', ep___channels_follow],
+	['channels/followed', ep___channels_followed],
+	['channels/owned', ep___channels_owned],
+	['channels/show', ep___channels_show],
+	['channels/timeline', ep___channels_timeline],
+	['channels/unfollow', ep___channels_unfollow],
+	['channels/update', ep___channels_update],
+	['charts/active-users', ep___charts_activeUsers],
+	['charts/ap-request', ep___charts_apRequest],
+	['charts/drive', ep___charts_drive],
+	['charts/federation', ep___charts_federation],
+	['charts/hashtag', ep___charts_hashtag],
+	['charts/instance', ep___charts_instance],
+	['charts/notes', ep___charts_notes],
+	['charts/user/drive', ep___charts_user_drive],
+	['charts/user/following', ep___charts_user_following],
+	['charts/user/notes', ep___charts_user_notes],
+	['charts/user/reactions', ep___charts_user_reactions],
+	['charts/users', ep___charts_users],
+	['clips/add-note', ep___clips_addNote],
+	['clips/create', ep___clips_create],
+	['clips/delete', ep___clips_delete],
+	['clips/list', ep___clips_list],
+	['clips/notes', ep___clips_notes],
+	['clips/show', ep___clips_show],
+	['clips/update', ep___clips_update],
+	['drive', ep___drive],
+	['drive/files', ep___drive_files],
+	['drive/files/attached-notes', ep___drive_files_attachedNotes],
+	['drive/files/check-existence', ep___drive_files_checkExistence],
+	['drive/files/create', ep___drive_files_create],
+	['drive/files/delete', ep___drive_files_delete],
+	['drive/files/find-by-hash', ep___drive_files_findByHash],
+	['drive/files/find', ep___drive_files_find],
+	['drive/files/show', ep___drive_files_show],
+	['drive/files/update', ep___drive_files_update],
+	['drive/files/upload-from-url', ep___drive_files_uploadFromUrl],
+	['drive/folders', ep___drive_folders],
+	['drive/folders/create', ep___drive_folders_create],
+	['drive/folders/delete', ep___drive_folders_delete],
+	['drive/folders/find', ep___drive_folders_find],
+	['drive/folders/show', ep___drive_folders_show],
+	['drive/folders/update', ep___drive_folders_update],
+	['drive/stream', ep___drive_stream],
+	['email-address/available', ep___emailAddress_available],
+	['endpoint', ep___endpoint],
+	['endpoints', ep___endpoints],
+	['export-custom-emojis', ep___exportCustomEmojis],
+	['federation/followers', ep___federation_followers],
+	['federation/following', ep___federation_following],
+	['federation/instances', ep___federation_instances],
+	['federation/show-instance', ep___federation_showInstance],
+	['federation/update-remote-user', ep___federation_updateRemoteUser],
+	['federation/users', ep___federation_users],
+	['following/create', ep___following_create],
+	['following/delete', ep___following_delete],
+	['following/invalidate', ep___following_invalidate],
+	['following/requests/accept', ep___following_requests_accept],
+	['following/requests/cancel', ep___following_requests_cancel],
+	['following/requests/list', ep___following_requests_list],
+	['following/requests/reject', ep___following_requests_reject],
+	['gallery/featured', ep___gallery_featured],
+	['gallery/popular', ep___gallery_popular],
+	['gallery/posts', ep___gallery_posts],
+	['gallery/posts/create', ep___gallery_posts_create],
+	['gallery/posts/delete', ep___gallery_posts_delete],
+	['gallery/posts/like', ep___gallery_posts_like],
+	['gallery/posts/show', ep___gallery_posts_show],
+	['gallery/posts/unlike', ep___gallery_posts_unlike],
+	['gallery/posts/update', ep___gallery_posts_update],
+	['get-online-users-count', ep___getOnlineUsersCount],
+	['hashtags/list', ep___hashtags_list],
+	['hashtags/search', ep___hashtags_search],
+	['hashtags/show', ep___hashtags_show],
+	['hashtags/trend', ep___hashtags_trend],
+	['hashtags/users', ep___hashtags_users],
+	['i', ep___i],
+	['i/2fa/done', ep___i_2fa_done],
+	['i/2fa/key-done', ep___i_2fa_keyDone],
+	['i/2fa/password-less', ep___i_2fa_passwordLess],
+	['i/2fa/register-key', ep___i_2fa_registerKey],
+	['i/2fa/register', ep___i_2fa_register],
+	['i/2fa/remove-key', ep___i_2fa_removeKey],
+	['i/2fa/unregister', ep___i_2fa_unregister],
+	['i/apps', ep___i_apps],
+	['i/authorized-apps', ep___i_authorizedApps],
+	['i/change-password', ep___i_changePassword],
+	['i/delete-account', ep___i_deleteAccount],
+	['i/export-blocking', ep___i_exportBlocking],
+	['i/export-following', ep___i_exportFollowing],
+	['i/export-mute', ep___i_exportMute],
+	['i/export-notes', ep___i_exportNotes],
+	['i/export-user-lists', ep___i_exportUserLists],
+	['i/favorites', ep___i_favorites],
+	['i/gallery/likes', ep___i_gallery_likes],
+	['i/gallery/posts', ep___i_gallery_posts],
+	['i/get-word-muted-notes-count', ep___i_getWordMutedNotesCount],
+	['i/import-blocking', ep___i_importBlocking],
+	['i/import-following', ep___i_importFollowing],
+	['i/import-muting', ep___i_importMuting],
+	['i/import-user-lists', ep___i_importUserLists],
+	['i/notifications', ep___i_notifications],
+	['i/page-likes', ep___i_pageLikes],
+	['i/pages', ep___i_pages],
+	['i/pin', ep___i_pin],
+	['i/read-all-messaging-messages', ep___i_readAllMessagingMessages],
+	['i/read-all-unread-notes', ep___i_readAllUnreadNotes],
+	['i/read-announcement', ep___i_readAnnouncement],
+	['i/regenerate-token', ep___i_regenerateToken],
+	['i/registry/get-all', ep___i_registry_getAll],
+	['i/registry/get-detail', ep___i_registry_getDetail],
+	['i/registry/get', ep___i_registry_get],
+	['i/registry/keys-with-type', ep___i_registry_keysWithType],
+	['i/registry/keys', ep___i_registry_keys],
+	['i/registry/remove', ep___i_registry_remove],
+	['i/registry/scopes', ep___i_registry_scopes],
+	['i/registry/set', ep___i_registry_set],
+	['i/revoke-token', ep___i_revokeToken],
+	['i/signin-history', ep___i_signinHistory],
+	['i/unpin', ep___i_unpin],
+	['i/update-email', ep___i_updateEmail],
+	['i/update', ep___i_update],
+	['i/user-group-invites', ep___i_userGroupInvites],
+	['messaging/history', ep___messaging_history],
+	['messaging/messages', ep___messaging_messages],
+	['messaging/messages/create', ep___messaging_messages_create],
+	['messaging/messages/delete', ep___messaging_messages_delete],
+	['messaging/messages/read', ep___messaging_messages_read],
+	['meta', ep___meta],
+	['miauth/gen-token', ep___miauth_genToken],
+	['mute/create', ep___mute_create],
+	['mute/delete', ep___mute_delete],
+	['mute/list', ep___mute_list],
+	['my/apps', ep___my_apps],
+	['notes', ep___notes],
+	['notes/children', ep___notes_children],
+	['notes/clips', ep___notes_clips],
+	['notes/conversation', ep___notes_conversation],
+	['notes/create', ep___notes_create],
+	['notes/delete', ep___notes_delete],
+	['notes/favorites/create', ep___notes_favorites_create],
+	['notes/favorites/delete', ep___notes_favorites_delete],
+	['notes/featured', ep___notes_featured],
+	['notes/global-timeline', ep___notes_globalTimeline],
+	['notes/hybrid-timeline', ep___notes_hybridTimeline],
+	['notes/local-timeline', ep___notes_localTimeline],
+	['notes/mentions', ep___notes_mentions],
+	['notes/polls/recommendation', ep___notes_polls_recommendation],
+	['notes/polls/vote', ep___notes_polls_vote],
+	['notes/reactions', ep___notes_reactions],
+	['notes/reactions/create', ep___notes_reactions_create],
+	['notes/reactions/delete', ep___notes_reactions_delete],
+	['notes/renotes', ep___notes_renotes],
+	['notes/replies', ep___notes_replies],
+	['notes/search-by-tag', ep___notes_searchByTag],
+	['notes/search', ep___notes_search],
+	['notes/show', ep___notes_show],
+	['notes/state', ep___notes_state],
+	['notes/thread-muting/create', ep___notes_threadMuting_create],
+	['notes/thread-muting/delete', ep___notes_threadMuting_delete],
+	['notes/timeline', ep___notes_timeline],
+	['notes/translate', ep___notes_translate],
+	['notes/unrenote', ep___notes_unrenote],
+	['notes/user-list-timeline', ep___notes_userListTimeline],
+	['notes/watching/create', ep___notes_watching_create],
+	['notes/watching/delete', ep___notes_watching_delete],
+	['notifications/create', ep___notifications_create],
+	['notifications/mark-all-as-read', ep___notifications_markAllAsRead],
+	['notifications/read', ep___notifications_read],
+	['page-push', ep___pagePush],
+	['pages/create', ep___pages_create],
+	['pages/delete', ep___pages_delete],
+	['pages/featured', ep___pages_featured],
+	['pages/like', ep___pages_like],
+	['pages/show', ep___pages_show],
+	['pages/unlike', ep___pages_unlike],
+	['pages/update', ep___pages_update],
+	['ping', ep___ping],
+	['pinned-users', ep___pinnedUsers],
+	['promo/read', ep___promo_read],
+	['request-reset-password', ep___requestResetPassword],
+	['reset-db', ep___resetDb],
+	['reset-password', ep___resetPassword],
+	['server-info', ep___serverInfo],
+	['stats', ep___stats],
+	['sw/register', ep___sw_register],
+	['sw/unregister', ep___sw_unregister],
+	['test', ep___test],
+	['username/available', ep___username_available],
+	['users', ep___users],
+	['users/clips', ep___users_clips],
+	['users/followers', ep___users_followers],
+	['users/following', ep___users_following],
+	['users/gallery/posts', ep___users_gallery_posts],
+	['users/get-frequently-replied-users', ep___users_getFrequentlyRepliedUsers],
+	['users/groups/create', ep___users_groups_create],
+	['users/groups/delete', ep___users_groups_delete],
+	['users/groups/invitations/accept', ep___users_groups_invitations_accept],
+	['users/groups/invitations/reject', ep___users_groups_invitations_reject],
+	['users/groups/invite', ep___users_groups_invite],
+	['users/groups/joined', ep___users_groups_joined],
+	['users/groups/leave', ep___users_groups_leave],
+	['users/groups/owned', ep___users_groups_owned],
+	['users/groups/pull', ep___users_groups_pull],
+	['users/groups/show', ep___users_groups_show],
+	['users/groups/transfer', ep___users_groups_transfer],
+	['users/groups/update', ep___users_groups_update],
+	['users/lists/create', ep___users_lists_create],
+	['users/lists/delete', ep___users_lists_delete],
+	['users/lists/list', ep___users_lists_list],
+	['users/lists/pull', ep___users_lists_pull],
+	['users/lists/push', ep___users_lists_push],
+	['users/lists/show', ep___users_lists_show],
+	['users/lists/update', ep___users_lists_update],
+	['users/notes', ep___users_notes],
+	['users/pages', ep___users_pages],
+	['users/reactions', ep___users_reactions],
+	['users/recommendation', ep___users_recommendation],
+	['users/relation', ep___users_relation],
+	['users/report-abuse', ep___users_reportAbuse],
+	['users/search-by-username-and-host', ep___users_searchByUsernameAndHost],
+	['users/search', ep___users_search],
+	['users/show', ep___users_show],
+	['users/stats', ep___users_stats],
+];
 
 export interface IEndpointMeta {
 	readonly stability?: 'deprecated' | 'experimental' | 'stable';
 
 	readonly tags?: ReadonlyArray<string>;
 
-	readonly params?: {
-		readonly [key: string]: Param;
-	};
-
 	readonly errors?: {
 		readonly [key: string]: {
 			readonly message: string;
@@ -99,25 +686,23 @@ export interface IEndpointMeta {
 	 * パーミッションの実現に利用されます。
 	 */
 	readonly kind?: string;
+
+	readonly description?: string;
 }
 
 export interface IEndpoint {
 	name: string;
 	exec: any;
 	meta: IEndpointMeta;
+	params: Schema;
 }
 
-const files = glob.sync('**/*.js', {
-	cwd: path.resolve(_dirname + '/endpoints/'),
-});
-
-const endpoints: IEndpoint[] = files.map(f => {
-	const ep = require(`./endpoints/${f}`);
-
+const endpoints: IEndpoint[] = eps.map(([name, ep]) => {
 	return {
-		name: f.replace('.js', ''),
+		name: name,
 		exec: ep.default,
 		meta: ep.meta || {},
+		params: ep.paramDef,
 	};
 });
 
diff --git a/packages/backend/src/server/api/endpoints/admin/abuse-user-reports.ts b/packages/backend/src/server/api/endpoints/admin/abuse-user-reports.ts
index ed7b146d03..333746f423 100644
--- a/packages/backend/src/server/api/endpoints/admin/abuse-user-reports.ts
+++ b/packages/backend/src/server/api/endpoints/admin/abuse-user-reports.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { AbuseUserReports } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { AbuseUserReports } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,49 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		state: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-
-		reporterOrigin: {
-			validator: $.optional.str.or([
-				'combined',
-				'local',
-				'remote',
-			]),
-			default: 'combined',
-		},
-
-		targetUserOrigin: {
-			validator: $.optional.str.or([
-				'combined',
-				'local',
-				'remote',
-			]),
-			default: 'combined',
-		},
-
-		forwarded: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -115,8 +70,22 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		state: { type: 'string', nullable: true, default: null },
+		reporterOrigin: { type: 'string', enum: ['combined', 'local', 'remote'], default: "combined" },
+		targetUserOrigin: { type: 'string', enum: ['combined', 'local', 'remote'], default: "combined" },
+		forwarded: { type: 'boolean', default: false },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const query = makePaginationQuery(AbuseUserReports.createQueryBuilder('report'), ps.sinceId, ps.untilId);
 
 	switch (ps.state) {
@@ -134,7 +103,7 @@ export default define(meta, async (ps) => {
 		case 'remote': query.andWhere('report.targetUserHost IS NOT NULL'); break;
 	}
 
-	const reports = await query.take(ps.limit!).getMany();
+	const reports = await query.take(ps.limit).getMany();
 
 	return await AbuseUserReports.packMany(reports);
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/accounts/create.ts b/packages/backend/src/server/api/endpoints/admin/accounts/create.ts
index 20f1232959..2820c7993d 100644
--- a/packages/backend/src/server/api/endpoints/admin/accounts/create.ts
+++ b/packages/backend/src/server/api/endpoints/admin/accounts/create.ts
@@ -1,20 +1,10 @@
-import define from '../../../define';
-import { Users } from '@/models/index';
-import { signup } from '../../../common/signup';
+import define from '../../../define.js';
+import { Users } from '@/models/index.js';
+import { signup } from '../../../common/signup.js';
 
 export const meta = {
 	tags: ['admin'],
 
-	params: {
-		username: {
-			validator: Users.validateLocalUsername,
-		},
-
-		password: {
-			validator: Users.validatePassword,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -28,8 +18,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		username: Users.localUsernameSchema,
+		password: Users.passwordSchema,
+	},
+	required: ['username', 'password'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, _me) => {
+export default define(meta, paramDef, async (ps, _me) => {
 	const me = _me ? await Users.findOneOrFail(_me.id) : null;
 	const noUsers = (await Users.count({
 		host: null,
diff --git a/packages/backend/src/server/api/endpoints/admin/accounts/delete.ts b/packages/backend/src/server/api/endpoints/admin/accounts/delete.ts
index 1701c1e3a7..01754ec8f3 100644
--- a/packages/backend/src/server/api/endpoints/admin/accounts/delete.ts
+++ b/packages/backend/src/server/api/endpoints/admin/accounts/delete.ts
@@ -1,26 +1,26 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Users } from '@/models/index';
-import { doPostSuspend } from '@/services/suspend-user';
-import { publishUserEvent } from '@/services/stream';
-import { createDeleteAccountJob } from '@/queue';
-import { ID } from '@/misc/cafy-id';
+import define from '../../../define.js';
+import { Users } from '@/models/index.js';
+import { doPostSuspend } from '@/services/suspend-user.js';
+import { publishUserEvent } from '@/services/stream.js';
+import { createDeleteAccountJob } from '@/queue/index.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/ad/create.ts b/packages/backend/src/server/api/endpoints/admin/ad/create.ts
index 00ad2012fe..ab2c50b50f 100644
--- a/packages/backend/src/server/api/endpoints/admin/ad/create.ts
+++ b/packages/backend/src/server/api/endpoints/admin/ad/create.ts
@@ -1,41 +1,30 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Ads } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../../define.js';
+import { Ads } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		url: {
-			validator: $.str.min(1),
-		},
-		memo: {
-			validator: $.str,
-		},
-		place: {
-			validator: $.str,
-		},
-		priority: {
-			validator: $.str,
-		},
-		ratio: {
-			validator: $.num.int().min(0),
-		},
-		expiresAt: {
-			validator: $.num.int(),
-		},
-		imageUrl: {
-			validator: $.str.min(1),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		url: { type: 'string', minLength: 1 },
+		memo: { type: 'string' },
+		place: { type: 'string' },
+		priority: { type: 'string' },
+		ratio: { type: 'integer' },
+		expiresAt: { type: 'integer' },
+		imageUrl: { type: 'string', minLength: 1 },
 	},
+	required: ['url', 'memo', 'place', 'priority', 'ratio', 'expiresAt', 'imageUrl'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	await Ads.insert({
 		id: genId(),
 		createdAt: new Date(),
diff --git a/packages/backend/src/server/api/endpoints/admin/ad/delete.ts b/packages/backend/src/server/api/endpoints/admin/ad/delete.ts
index c0124e2484..3663d974c5 100644
--- a/packages/backend/src/server/api/endpoints/admin/ad/delete.ts
+++ b/packages/backend/src/server/api/endpoints/admin/ad/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Ads } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { Ads } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,12 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		id: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchAd: {
 			message: 'No such ad.',
@@ -25,8 +17,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		id: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['id'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const ad = await Ads.findOne(ps.id);
 
 	if (ad == null) throw new ApiError(meta.errors.noSuchAd);
diff --git a/packages/backend/src/server/api/endpoints/admin/ad/list.ts b/packages/backend/src/server/api/endpoints/admin/ad/list.ts
index 7a83637f3b..74f154f272 100644
--- a/packages/backend/src/server/api/endpoints/admin/ad/list.ts
+++ b/packages/backend/src/server/api/endpoints/admin/ad/list.ts
@@ -1,37 +1,30 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { Ads } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
+import define from '../../../define.js';
+import { Ads } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const query = makePaginationQuery(Ads.createQueryBuilder('ad'), ps.sinceId, ps.untilId)
 		.andWhere('ad.expiresAt > :now', { now: new Date() });
 
-	const ads = await query.take(ps.limit!).getMany();
+	const ads = await query.take(ps.limit).getMany();
 
 	return ads;
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/ad/update.ts b/packages/backend/src/server/api/endpoints/admin/ad/update.ts
index c2b09ab9cf..89c421db66 100644
--- a/packages/backend/src/server/api/endpoints/admin/ad/update.ts
+++ b/packages/backend/src/server/api/endpoints/admin/ad/update.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Ads } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { Ads } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,33 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		id: {
-			validator: $.type(ID),
-		},
-		memo: {
-			validator: $.str,
-		},
-		url: {
-			validator: $.str.min(1),
-		},
-		imageUrl: {
-			validator: $.str.min(1),
-		},
-		place: {
-			validator: $.str,
-		},
-		priority: {
-			validator: $.str,
-		},
-		ratio: {
-			validator: $.num.int().min(0),
-		},
-		expiresAt: {
-			validator: $.num.int(),
-		},
-	},
-
 	errors: {
 		noSuchAd: {
 			message: 'No such ad.',
@@ -46,8 +17,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		id: { type: 'string', format: 'misskey:id' },
+		memo: { type: 'string' },
+		url: { type: 'string', minLength: 1 },
+		imageUrl: { type: 'string', minLength: 1 },
+		place: { type: 'string' },
+		priority: { type: 'string' },
+		ratio: { type: 'integer' },
+		expiresAt: { type: 'integer' },
+	},
+	required: ['id', 'memo', 'url', 'imageUrl', 'place', 'priority', 'ratio', 'expiresAt'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const ad = await Ads.findOne(ps.id);
 
 	if (ad == null) throw new ApiError(meta.errors.noSuchAd);
diff --git a/packages/backend/src/server/api/endpoints/admin/announcements/create.ts b/packages/backend/src/server/api/endpoints/admin/announcements/create.ts
index 24c4caa37d..41570078d4 100644
--- a/packages/backend/src/server/api/endpoints/admin/announcements/create.ts
+++ b/packages/backend/src/server/api/endpoints/admin/announcements/create.ts
@@ -1,7 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Announcements } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../../define.js';
+import { Announcements } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -9,18 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		title: {
-			validator: $.str.min(1),
-		},
-		text: {
-			validator: $.str.min(1),
-		},
-		imageUrl: {
-			validator: $.nullable.str.min(1),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -57,8 +44,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		title: { type: 'string', minLength: 1 },
+		text: { type: 'string', minLength: 1 },
+		imageUrl: { type: 'string', nullable: true, minLength: 1 },
+	},
+	required: ['title', 'text', 'imageUrl'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const announcement = await Announcements.insert({
 		id: genId(),
 		createdAt: new Date(),
@@ -68,5 +65,5 @@ export default define(meta, async (ps) => {
 		imageUrl: ps.imageUrl,
 	}).then(x => Announcements.findOneOrFail(x.identifiers[0]));
 
-	return announcement;
+	return Object.assign({}, announcement, { createdAt: announcement.createdAt.toISOString(), updatedAt: null });
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/announcements/delete.ts b/packages/backend/src/server/api/endpoints/admin/announcements/delete.ts
index 5548f99006..4871dc4e12 100644
--- a/packages/backend/src/server/api/endpoints/admin/announcements/delete.ts
+++ b/packages/backend/src/server/api/endpoints/admin/announcements/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Announcements } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { Announcements } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,12 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		id: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchAnnouncement: {
 			message: 'No such announcement.',
@@ -25,8 +17,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		id: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['id'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const announcement = await Announcements.findOne(ps.id);
 
 	if (announcement == null) throw new ApiError(meta.errors.noSuchAnnouncement);
diff --git a/packages/backend/src/server/api/endpoints/admin/announcements/list.ts b/packages/backend/src/server/api/endpoints/admin/announcements/list.ts
index e5cc53ccdd..0ba0a8ee08 100644
--- a/packages/backend/src/server/api/endpoints/admin/announcements/list.ts
+++ b/packages/backend/src/server/api/endpoints/admin/announcements/list.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { Announcements, AnnouncementReads } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
+import define from '../../../define.js';
+import { Announcements, AnnouncementReads } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,21 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -69,11 +52,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const query = makePaginationQuery(Announcements.createQueryBuilder('announcement'), ps.sinceId, ps.untilId);
 
-	const announcements = await query.take(ps.limit!).getMany();
+	const announcements = await query.take(ps.limit).getMany();
 
 	for (const announcement of announcements) {
 		(announcement as any).reads = await AnnouncementReads.count({
diff --git a/packages/backend/src/server/api/endpoints/admin/announcements/update.ts b/packages/backend/src/server/api/endpoints/admin/announcements/update.ts
index f66293bb18..138337ef5b 100644
--- a/packages/backend/src/server/api/endpoints/admin/announcements/update.ts
+++ b/packages/backend/src/server/api/endpoints/admin/announcements/update.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Announcements } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { Announcements } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,21 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		id: {
-			validator: $.type(ID),
-		},
-		title: {
-			validator: $.str.min(1),
-		},
-		text: {
-			validator: $.str.min(1),
-		},
-		imageUrl: {
-			validator: $.nullable.str.min(1),
-		},
-	},
-
 	errors: {
 		noSuchAnnouncement: {
 			message: 'No such announcement.',
@@ -34,8 +17,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		id: { type: 'string', format: 'misskey:id' },
+		title: { type: 'string', minLength: 1 },
+		text: { type: 'string', minLength: 1 },
+		imageUrl: { type: 'string', nullable: true, minLength: 1 },
+	},
+	required: ['id', 'title', 'text', 'imageUrl'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const announcement = await Announcements.findOne(ps.id);
 
 	if (announcement == null) throw new ApiError(meta.errors.noSuchAnnouncement);
diff --git a/packages/backend/src/server/api/endpoints/admin/delete-all-files-of-a-user.ts b/packages/backend/src/server/api/endpoints/admin/delete-all-files-of-a-user.ts
index 249e63a0f8..90e65ec4cd 100644
--- a/packages/backend/src/server/api/endpoints/admin/delete-all-files-of-a-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/delete-all-files-of-a-user.ts
@@ -1,24 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { deleteFile } from '@/services/drive/delete-file';
-import { DriveFiles } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
+import define from '../../define.js';
+import { deleteFile } from '@/services/drive/delete-file.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const files = await DriveFiles.find({
 		userId: ps.userId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/drive/clean-remote-files.ts b/packages/backend/src/server/api/endpoints/admin/drive/clean-remote-files.ts
index acabbfef5c..bab149532e 100644
--- a/packages/backend/src/server/api/endpoints/admin/drive/clean-remote-files.ts
+++ b/packages/backend/src/server/api/endpoints/admin/drive/clean-remote-files.ts
@@ -1,5 +1,5 @@
-import define from '../../../define';
-import { createCleanRemoteFilesJob } from '@/queue/index';
+import define from '../../../define.js';
+import { createCleanRemoteFilesJob } from '@/queue/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -8,7 +8,13 @@ export const meta = {
 	requireModerator: true,
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	createCleanRemoteFilesJob();
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/drive/cleanup.ts b/packages/backend/src/server/api/endpoints/admin/drive/cleanup.ts
index 452e7069a8..3e7d43fb0b 100644
--- a/packages/backend/src/server/api/endpoints/admin/drive/cleanup.ts
+++ b/packages/backend/src/server/api/endpoints/admin/drive/cleanup.ts
@@ -1,7 +1,7 @@
 import { IsNull } from 'typeorm';
-import define from '../../../define';
-import { deleteFile } from '@/services/drive/delete-file';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { deleteFile } from '@/services/drive/delete-file.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,8 +10,14 @@ export const meta = {
 	requireModerator: true,
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const files = await DriveFiles.find({
 		userId: IsNull(),
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/drive/files.ts b/packages/backend/src/server/api/endpoints/admin/drive/files.ts
index 264f549867..646d85a1e0 100644
--- a/packages/backend/src/server/api/endpoints/admin/drive/files.ts
+++ b/packages/backend/src/server/api/endpoints/admin/drive/files.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { DriveFiles } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
-import { ID } from '@/misc/cafy-id';
+import define from '../../../define.js';
+import { DriveFiles } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,39 +8,6 @@ export const meta = {
 	requireCredential: false,
 	requireModerator: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		type: {
-			validator: $.optional.nullable.str.match(/^[a-zA-Z0-9\/\-*]+$/),
-		},
-
-		origin: {
-			validator: $.optional.str.or([
-				'combined',
-				'local',
-				'remote',
-			]),
-			default: 'local',
-		},
-
-		hostname: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -54,8 +19,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		type: { type: 'string', nullable: true, pattern: /^[a-zA-Z0-9\/\-*]+$/.toString().slice(1, -1) },
+		origin: { type: 'string', enum: ['combined', 'local', 'remote'], default: "local" },
+		hostname: { type: 'string', nullable: true, default: null },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(DriveFiles.createQueryBuilder('file'), ps.sinceId, ps.untilId);
 
 	if (ps.origin === 'local') {
@@ -76,7 +54,7 @@ export default define(meta, async (ps, me) => {
 		}
 	}
 
-	const files = await query.take(ps.limit!).getMany();
+	const files = await query.take(ps.limit).getMany();
 
 	return await DriveFiles.packMany(files, { detail: true, withUser: true, self: true });
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/drive/show-file.ts b/packages/backend/src/server/api/endpoints/admin/drive/show-file.ts
index 5d9a1f2703..e821160095 100644
--- a/packages/backend/src/server/api/endpoints/admin/drive/show-file.ts
+++ b/packages/backend/src/server/api/endpoints/admin/drive/show-file.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,16 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		fileId: {
-			validator: $.optional.type(ID),
-		},
-
-		url: {
-			validator: $.optional.str,
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -161,8 +149,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+		url: { type: 'string' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const file = ps.fileId ? await DriveFiles.findOne(ps.fileId) : await DriveFiles.findOne({
 		where: [{
 			url: ps.url,
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/add-aliases-bulk.ts b/packages/backend/src/server/api/endpoints/admin/emoji/add-aliases-bulk.ts
index f0fd73c276..77a4adea61 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/add-aliases-bulk.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/add-aliases-bulk.ts
@@ -1,29 +1,30 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection, In } from 'typeorm';
-import { ApiError } from '../../../error';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		ids: {
-			validator: $.arr($.type(ID)),
-		},
-
-		aliases: {
-			validator: $.arr($.str),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		ids: { type: 'array', items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		aliases: { type: 'array', items: {
+			type: 'string',
+		} },
 	},
+	required: ['ids', 'aliases'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const emojis = await Emojis.find({
 		id: In(ps.ids),
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
index 1dfeae262f..c5787d59dc 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/add.ts
@@ -1,13 +1,11 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Emojis, DriveFiles } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../../define.js';
+import { Emojis, DriveFiles } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 import { getConnection } from 'typeorm';
-import { insertModerationLog } from '@/services/insert-moderation-log';
-import { ApiError } from '../../../error';
-import { ID } from '@/misc/cafy-id';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
+import { ApiError } from '../../../error.js';
 import rndstr from 'rndstr';
-import { publishBroadcastStream } from '@/services/stream';
+import { publishBroadcastStream } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -15,12 +13,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -30,8 +22,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) throw new ApiError(meta.errors.noSuchFile);
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/copy.ts b/packages/backend/src/server/api/endpoints/admin/emoji/copy.ts
index 17cbf208aa..a0eaa61258 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/copy.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/copy.ts
@@ -1,13 +1,11 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Emojis } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 import { getConnection } from 'typeorm';
-import { ApiError } from '../../../error';
-import { DriveFile } from '@/models/entities/drive-file';
-import { ID } from '@/misc/cafy-id';
-import { uploadFromUrl } from '@/services/drive/upload-from-url';
-import { publishBroadcastStream } from '@/services/stream';
+import { ApiError } from '../../../error.js';
+import { DriveFile } from '@/models/entities/drive-file.js';
+import { uploadFromUrl } from '@/services/drive/upload-from-url.js';
+import { publishBroadcastStream } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -15,12 +13,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		emojiId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchEmoji: {
 			message: 'No such emoji.',
@@ -42,8 +34,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		emojiId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['emojiId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const emoji = await Emojis.findOne(ps.emojiId);
 
 	if (emoji == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/delete-bulk.ts b/packages/backend/src/server/api/endpoints/admin/emoji/delete-bulk.ts
index 797a5de672..38a2d65cf6 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/delete-bulk.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/delete-bulk.ts
@@ -1,26 +1,28 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection, In } from 'typeorm';
-import { insertModerationLog } from '@/services/insert-moderation-log';
-import { ApiError } from '../../../error';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		ids: {
-			validator: $.arr($.type(ID)),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		ids: { type: 'array', items: {
+			type: 'string', format: 'misskey:id',
+		} },
 	},
+	required: ['ids'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const emojis = await Emojis.find({
 		id: In(ps.ids),
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/delete.ts b/packages/backend/src/server/api/endpoints/admin/emoji/delete.ts
index 1580439024..a0cffb47f8 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/delete.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/delete.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection } from 'typeorm';
-import { insertModerationLog } from '@/services/insert-moderation-log';
-import { ApiError } from '../../../error';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -12,12 +10,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		id: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchEmoji: {
 			message: 'No such emoji.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		id: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['id'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const emoji = await Emojis.findOne(ps.id);
 
 	if (emoji == null) throw new ApiError(meta.errors.noSuchEmoji);
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/import-zip.ts b/packages/backend/src/server/api/endpoints/admin/emoji/import-zip.ts
index 8856a38f24..3f03dc2da4 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/import-zip.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/import-zip.ts
@@ -1,21 +1,22 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { createImportCustomEmojisJob } from '@/queue/index';
+import define from '../../../define.js';
+import { createImportCustomEmojisJob } from '@/queue/index.js';
 import ms from 'ms';
-import { ID } from '@/misc/cafy-id';
 
 export const meta = {
 	secure: true,
 	requireCredential: true,
 	requireModerator: true,
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['fileId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createImportCustomEmojisJob(user, ps.fileId);
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/list-remote.ts b/packages/backend/src/server/api/endpoints/admin/emoji/list-remote.ts
index 6e502547f5..f19c3ddbd8 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/list-remote.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/list-remote.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Emojis } from '@/models/index';
-import { toPuny } from '@/misc/convert-host';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
-import { ID } from '@/misc/cafy-id';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
+import { toPuny } from '@/misc/convert-host.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -11,31 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		query: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-
-		host: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -77,8 +50,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		query: { type: 'string', nullable: true, default: null },
+		host: { type: 'string', nullable: true, default: null },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const q = makePaginationQuery(Emojis.createQueryBuilder('emoji'), ps.sinceId, ps.untilId);
 
 	if (ps.host == null) {
@@ -93,7 +78,7 @@ export default define(meta, async (ps) => {
 
 	const emojis = await q
 		.orderBy('emoji.id', 'DESC')
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return Emojis.packMany(emojis);
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/list.ts b/packages/backend/src/server/api/endpoints/admin/emoji/list.ts
index 76ef190f94..f488a71a00 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/list.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/list.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Emojis } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
-import { ID } from '@/misc/cafy-id';
-import { Emoji } from '@/models/entities/emoji';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
+import { Emoji } from '@/models/entities/emoji.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -11,26 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		query: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -72,8 +50,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		query: { type: 'string', nullable: true, default: null },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const q = makePaginationQuery(Emojis.createQueryBuilder('emoji'), ps.sinceId, ps.untilId)
 		.andWhere(`emoji.host IS NULL`);
 
@@ -81,7 +70,7 @@ export default define(meta, async (ps) => {
 
 	if (ps.query) {
 		//q.andWhere('emoji.name ILIKE :q', { q: `%${ps.query}%` });
-		//const emojis = await q.take(ps.limit!).getMany();
+		//const emojis = await q.take(ps.limit).getMany();
 
 		emojis = await q.getMany();
 
@@ -90,9 +79,9 @@ export default define(meta, async (ps) => {
 			emoji.aliases.some(a => a.includes(ps.query!)) ||
 			emoji.category?.includes(ps.query!));
 
-		emojis.splice(ps.limit! + 1);
+		emojis.splice(ps.limit + 1);
 	} else {
-		emojis = await q.take(ps.limit!).getMany();
+		emojis = await q.take(ps.limit).getMany();
 	}
 
 	return Emojis.packMany(emojis);
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/remove-aliases-bulk.ts b/packages/backend/src/server/api/endpoints/admin/emoji/remove-aliases-bulk.ts
index c49f84b7fb..dbad93d336 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/remove-aliases-bulk.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/remove-aliases-bulk.ts
@@ -1,29 +1,30 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection, In } from 'typeorm';
-import { ApiError } from '../../../error';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		ids: {
-			validator: $.arr($.type(ID)),
-		},
-
-		aliases: {
-			validator: $.arr($.str),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		ids: { type: 'array', items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		aliases: { type: 'array', items: {
+			type: 'string',
+		} },
 	},
+	required: ['ids', 'aliases'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const emojis = await Emojis.find({
 		id: In(ps.ids),
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/set-aliases-bulk.ts b/packages/backend/src/server/api/endpoints/admin/emoji/set-aliases-bulk.ts
index 06197820f0..470b9bef08 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/set-aliases-bulk.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/set-aliases-bulk.ts
@@ -1,29 +1,30 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection, In } from 'typeorm';
-import { ApiError } from '../../../error';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		ids: {
-			validator: $.arr($.type(ID)),
-		},
-
-		aliases: {
-			validator: $.arr($.str),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		ids: { type: 'array', items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		aliases: { type: 'array', items: {
+			type: 'string',
+		} },
 	},
+	required: ['ids', 'aliases'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	await Emojis.update({
 		id: In(ps.ids),
 	}, {
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/set-category-bulk.ts b/packages/backend/src/server/api/endpoints/admin/emoji/set-category-bulk.ts
index f0645f111b..40e4c0199e 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/set-category-bulk.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/set-category-bulk.ts
@@ -1,29 +1,28 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection, In } from 'typeorm';
-import { ApiError } from '../../../error';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		ids: {
-			validator: $.arr($.type(ID)),
-		},
-
-		category: {
-			validator: $.optional.nullable.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		ids: { type: 'array', items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		category: { type: 'string', nullable: true },
 	},
+	required: ['ids'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	await Emojis.update({
 		id: In(ps.ids),
 	}, {
diff --git a/packages/backend/src/server/api/endpoints/admin/emoji/update.ts b/packages/backend/src/server/api/endpoints/admin/emoji/update.ts
index 54a2cf9517..c6d07e16fa 100644
--- a/packages/backend/src/server/api/endpoints/admin/emoji/update.ts
+++ b/packages/backend/src/server/api/endpoints/admin/emoji/update.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { Emojis } from '@/models/index';
+import define from '../../../define.js';
+import { Emojis } from '@/models/index.js';
 import { getConnection } from 'typeorm';
-import { ApiError } from '../../../error';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -11,24 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		id: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.str,
-		},
-
-		category: {
-			validator: $.optional.nullable.str,
-		},
-
-		aliases: {
-			validator: $.arr($.str),
-		},
-	},
-
 	errors: {
 		noSuchEmoji: {
 			message: 'No such emoji.',
@@ -38,8 +18,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		id: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string' },
+		category: { type: 'string', nullable: true },
+		aliases: { type: 'array', items: {
+			type: 'string',
+		} },
+	},
+	required: ['id', 'name', 'aliases'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const emoji = await Emojis.findOne(ps.id);
 
 	if (emoji == null) throw new ApiError(meta.errors.noSuchEmoji);
diff --git a/packages/backend/src/server/api/endpoints/admin/federation/delete-all-files.ts b/packages/backend/src/server/api/endpoints/admin/federation/delete-all-files.ts
index db023c6f0b..d4251f2feb 100644
--- a/packages/backend/src/server/api/endpoints/admin/federation/delete-all-files.ts
+++ b/packages/backend/src/server/api/endpoints/admin/federation/delete-all-files.ts
@@ -1,23 +1,24 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { deleteFile } from '@/services/drive/delete-file';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { deleteFile } from '@/services/drive/delete-file.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		host: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
 	},
+	required: ['host'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const files = await DriveFiles.find({
 		userHost: ps.host,
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/federation/refresh-remote-instance-metadata.ts b/packages/backend/src/server/api/endpoints/admin/federation/refresh-remote-instance-metadata.ts
index b68252ef2e..86978cc309 100644
--- a/packages/backend/src/server/api/endpoints/admin/federation/refresh-remote-instance-metadata.ts
+++ b/packages/backend/src/server/api/endpoints/admin/federation/refresh-remote-instance-metadata.ts
@@ -1,24 +1,25 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Instances } from '@/models/index';
-import { toPuny } from '@/misc/convert-host';
-import { fetchInstanceMetadata } from '@/services/fetch-instance-metadata';
+import define from '../../../define.js';
+import { Instances } from '@/models/index.js';
+import { toPuny } from '@/misc/convert-host.js';
+import { fetchInstanceMetadata } from '@/services/fetch-instance-metadata.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		host: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
 	},
+	required: ['host'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const instance = await Instances.findOne({ host: toPuny(ps.host) });
 
 	if (instance == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/federation/remove-all-following.ts b/packages/backend/src/server/api/endpoints/admin/federation/remove-all-following.ts
index 4de8ad1336..ccd07489cb 100644
--- a/packages/backend/src/server/api/endpoints/admin/federation/remove-all-following.ts
+++ b/packages/backend/src/server/api/endpoints/admin/federation/remove-all-following.ts
@@ -1,23 +1,24 @@
-import $ from 'cafy';
-import define from '../../../define';
-import deleteFollowing from '@/services/following/delete';
-import { Followings, Users } from '@/models/index';
+import define from '../../../define.js';
+import deleteFollowing from '@/services/following/delete.js';
+import { Followings, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		host: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
 	},
+	required: ['host'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const followings = await Followings.find({
 		followerHost: ps.host,
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts b/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts
index 6ac2f1f467..1981082428 100644
--- a/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts
+++ b/packages/backend/src/server/api/endpoints/admin/federation/update-instance.ts
@@ -1,27 +1,25 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Instances } from '@/models/index';
-import { toPuny } from '@/misc/convert-host';
+import define from '../../../define.js';
+import { Instances } from '@/models/index.js';
+import { toPuny } from '@/misc/convert-host.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		host: {
-			validator: $.str,
-		},
-
-		isSuspended: {
-			validator: $.bool,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
+		isSuspended: { type: 'boolean' },
 	},
+	required: ['host', 'isSuspended'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const instance = await Instances.findOne({ host: toPuny(ps.host) });
 
 	if (instance == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts b/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts
index 9a2bccec77..37878c4143 100644
--- a/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts
+++ b/packages/backend/src/server/api/endpoints/admin/get-index-stats.ts
@@ -1,4 +1,4 @@
-import define from '../../define';
+import define from '../../define.js';
 import { getConnection } from 'typeorm';
 
 export const meta = {
@@ -6,13 +6,16 @@ export const meta = {
 	requireModerator: true,
 
 	tags: ['admin'],
+} as const;
 
-	params: {
-	},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const stats = await
 		getConnection().query(`SELECT * FROM pg_indexes;`)
 		.then(recs => {
diff --git a/packages/backend/src/server/api/endpoints/admin/get-table-stats.ts b/packages/backend/src/server/api/endpoints/admin/get-table-stats.ts
index 1c5f250676..7cf2d5ffd4 100644
--- a/packages/backend/src/server/api/endpoints/admin/get-table-stats.ts
+++ b/packages/backend/src/server/api/endpoints/admin/get-table-stats.ts
@@ -1,4 +1,4 @@
-import define from '../../define';
+import define from '../../define.js';
 import { getConnection } from 'typeorm';
 
 export const meta = {
@@ -7,9 +7,6 @@ export const meta = {
 
 	tags: ['admin'],
 
-	params: {
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -22,8 +19,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const sizes = await
 		getConnection().query(`
 			SELECT relname AS "table", reltuples as "count", pg_total_relation_size(C.oid) AS "size"
diff --git a/packages/backend/src/server/api/endpoints/admin/invite.ts b/packages/backend/src/server/api/endpoints/admin/invite.ts
index 3428709c04..7e950cf87b 100644
--- a/packages/backend/src/server/api/endpoints/admin/invite.ts
+++ b/packages/backend/src/server/api/endpoints/admin/invite.ts
@@ -1,7 +1,7 @@
 import rndstr from 'rndstr';
-import define from '../../define';
-import { RegistrationTickets } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../define.js';
+import { RegistrationTickets } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -9,8 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -26,8 +24,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const code = rndstr({
 		length: 8,
 		chars: '2-9A-HJ-NP-Z', // [0-9A-Z] w/o [01IO] (32 patterns)
diff --git a/packages/backend/src/server/api/endpoints/admin/moderators/add.ts b/packages/backend/src/server/api/endpoints/admin/moderators/add.ts
index 0308cf2761..4206e3a3c2 100644
--- a/packages/backend/src/server/api/endpoints/admin/moderators/add.ts
+++ b/packages/backend/src/server/api/endpoints/admin/moderators/add.ts
@@ -1,23 +1,23 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { Users } from '@/models/index';
+import define from '../../../define.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireAdmin: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/moderators/remove.ts b/packages/backend/src/server/api/endpoints/admin/moderators/remove.ts
index bdb976e9ec..143119bfe4 100644
--- a/packages/backend/src/server/api/endpoints/admin/moderators/remove.ts
+++ b/packages/backend/src/server/api/endpoints/admin/moderators/remove.ts
@@ -1,23 +1,23 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { Users } from '@/models/index';
+import define from '../../../define.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireAdmin: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/promo/create.ts b/packages/backend/src/server/api/endpoints/admin/promo/create.ts
index f2735ac9f8..2eec5bf0db 100644
--- a/packages/backend/src/server/api/endpoints/admin/promo/create.ts
+++ b/packages/backend/src/server/api/endpoints/admin/promo/create.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getNote } from '../../../common/getters';
-import { PromoNotes } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getNote } from '../../../common/getters.js';
+import { PromoNotes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -11,16 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		expiresAt: {
-			validator: $.num.int(),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -36,8 +24,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		expiresAt: { type: 'integer' },
+	},
+	required: ['noteId', 'expiresAt'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
@@ -51,7 +48,6 @@ export default define(meta, async (ps, user) => {
 
 	await PromoNotes.insert({
 		noteId: note.id,
-		createdAt: new Date(),
 		expiresAt: new Date(ps.expiresAt),
 		userId: note.userId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/admin/queue/clear.ts b/packages/backend/src/server/api/endpoints/admin/queue/clear.ts
index 3c8e7a27a2..8f015c280a 100644
--- a/packages/backend/src/server/api/endpoints/admin/queue/clear.ts
+++ b/packages/backend/src/server/api/endpoints/admin/queue/clear.ts
@@ -1,18 +1,22 @@
-import define from '../../../define';
-import { destroy } from '@/queue/index';
-import { insertModerationLog } from '@/services/insert-moderation-log';
+import define from '../../../define.js';
+import { destroy } from '@/queue/index.js';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	destroy();
 
 	insertModerationLog(me, 'clearQueue');
diff --git a/packages/backend/src/server/api/endpoints/admin/queue/deliver-delayed.ts b/packages/backend/src/server/api/endpoints/admin/queue/deliver-delayed.ts
index 4760e2c310..70f7d77de4 100644
--- a/packages/backend/src/server/api/endpoints/admin/queue/deliver-delayed.ts
+++ b/packages/backend/src/server/api/endpoints/admin/queue/deliver-delayed.ts
@@ -1,6 +1,6 @@
-import { deliverQueue } from '@/queue/queues';
-import { URL } from 'url';
-import define from '../../../define';
+import { deliverQueue } from '@/queue/queues.js';
+import { URL } from 'node:url';
+import define from '../../../define.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -8,9 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -35,8 +32,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const jobs = await deliverQueue.getJobs(['delayed']);
 
 	const res = [] as [string, number][];
diff --git a/packages/backend/src/server/api/endpoints/admin/queue/inbox-delayed.ts b/packages/backend/src/server/api/endpoints/admin/queue/inbox-delayed.ts
index a95aabc506..2235ce8f97 100644
--- a/packages/backend/src/server/api/endpoints/admin/queue/inbox-delayed.ts
+++ b/packages/backend/src/server/api/endpoints/admin/queue/inbox-delayed.ts
@@ -1,6 +1,6 @@
-import { URL } from 'url';
-import define from '../../../define';
-import { inboxQueue } from '@/queue/queues';
+import { URL } from 'node:url';
+import define from '../../../define.js';
+import { inboxQueue } from '@/queue/queues.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -8,9 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -35,8 +32,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const jobs = await inboxQueue.getJobs(['delayed']);
 
 	const res = [] as [string, number][];
diff --git a/packages/backend/src/server/api/endpoints/admin/queue/jobs.ts b/packages/backend/src/server/api/endpoints/admin/queue/jobs.ts
deleted file mode 100644
index df0b4a8f13..0000000000
--- a/packages/backend/src/server/api/endpoints/admin/queue/jobs.ts
+++ /dev/null
@@ -1,82 +0,0 @@
-import { deliverQueue, inboxQueue, dbQueue, objectStorageQueue } from '@/queue/queues';
-import $ from 'cafy';
-import define from '../../../define';
-
-export const meta = {
-	tags: ['admin'],
-
-	requireCredential: true,
-	requireModerator: true,
-
-	params: {
-		domain: {
-			validator: $.str.or(['deliver', 'inbox', 'db', 'objectStorage']),
-		},
-
-		state: {
-			validator: $.str.or(['active', 'waiting', 'delayed']),
-		},
-
-		limit: {
-			validator: $.optional.num,
-			default: 50,
-		},
-	},
-
-	res: {
-		type: 'array',
-		optional: false, nullable: false,
-		items: {
-			type: 'object',
-			optional: false, nullable: false,
-			properties: {
-				id: {
-					type: 'string',
-					optional: false, nullable: false,
-					format: 'id',
-				},
-				data: {
-					type: 'object',
-					optional: false, nullable: false,
-				},
-				attempts: {
-					type: 'number',
-					optional: false, nullable: false,
-				},
-				maxAttempts: {
-					type: 'number',
-					optional: false, nullable: false,
-				},
-				timestamp: {
-					type: 'number',
-					optional: false, nullable: false,
-				},
-			},
-		},
-	},
-} as const;
-
-// eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	const queue =
-		ps.domain === 'deliver' ? deliverQueue :
-		ps.domain === 'inbox' ? inboxQueue :
-		ps.domain === 'db' ? dbQueue :
-		ps.domain === 'objectStorage' ? objectStorageQueue :
-		null as never;
-
-	const jobs = await queue.getJobs([ps.state], 0, ps.limit!);
-
-	return jobs.map(job => {
-		const data = job.data;
-		delete data.content;
-		delete data.user;
-		return {
-			id: job.id,
-			data,
-			attempts: job.attemptsMade,
-			maxAttempts: job.opts ? job.opts.attempts : 0,
-			timestamp: job.timestamp,
-		};
-	});
-});
diff --git a/packages/backend/src/server/api/endpoints/admin/queue/stats.ts b/packages/backend/src/server/api/endpoints/admin/queue/stats.ts
index dab0be5dbc..988b5a5e35 100644
--- a/packages/backend/src/server/api/endpoints/admin/queue/stats.ts
+++ b/packages/backend/src/server/api/endpoints/admin/queue/stats.ts
@@ -1,5 +1,5 @@
-import { deliverQueue, inboxQueue, dbQueue, objectStorageQueue } from '@/queue/queues';
-import define from '../../../define';
+import { deliverQueue, inboxQueue, dbQueue, objectStorageQueue } from '@/queue/queues.js';
+import define from '../../../define.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -7,8 +7,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -33,8 +31,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const deliverJobCounts = await deliverQueue.getJobCounts();
 	const inboxJobCounts = await inboxQueue.getJobCounts();
 	const dbJobCounts = await dbQueue.getJobCounts();
diff --git a/packages/backend/src/server/api/endpoints/admin/relays/add.ts b/packages/backend/src/server/api/endpoints/admin/relays/add.ts
index 65890a00f7..348e9baca1 100644
--- a/packages/backend/src/server/api/endpoints/admin/relays/add.ts
+++ b/packages/backend/src/server/api/endpoints/admin/relays/add.ts
@@ -1,8 +1,7 @@
-import { URL } from 'url';
-import $ from 'cafy';
-import define from '../../../define';
-import { addRelay } from '@/services/relay';
-import { ApiError } from '../../../error';
+import { URL } from 'node:url';
+import define from '../../../define.js';
+import { addRelay } from '@/services/relay.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,12 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		inbox: {
-			validator: $.str,
-		},
-	},
-
 	errors: {
 		invalidUrl: {
 			message: 'Invalid URL',
@@ -52,8 +45,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		inbox: { type: 'string' },
+	},
+	required: ['inbox'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	try {
 		if (new URL(ps.inbox).protocol !== 'https:') throw 'https only';
 	} catch {
diff --git a/packages/backend/src/server/api/endpoints/admin/relays/list.ts b/packages/backend/src/server/api/endpoints/admin/relays/list.ts
index bdddf13374..89ec651e61 100644
--- a/packages/backend/src/server/api/endpoints/admin/relays/list.ts
+++ b/packages/backend/src/server/api/endpoints/admin/relays/list.ts
@@ -1,5 +1,5 @@
-import define from '../../../define';
-import { listRelay } from '@/services/relay';
+import define from '../../../define.js';
+import { listRelay } from '@/services/relay.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -7,9 +7,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -42,7 +39,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	return await listRelay();
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/relays/remove.ts b/packages/backend/src/server/api/endpoints/admin/relays/remove.ts
index 4b04e620c1..b59cf72c58 100644
--- a/packages/backend/src/server/api/endpoints/admin/relays/remove.ts
+++ b/packages/backend/src/server/api/endpoints/admin/relays/remove.ts
@@ -1,21 +1,22 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { removeRelay } from '@/services/relay';
+import define from '../../../define.js';
+import { removeRelay } from '@/services/relay.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		inbox: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		inbox: { type: 'string' },
 	},
+	required: ['inbox'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	return await removeRelay(ps.inbox);
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/reset-password.ts b/packages/backend/src/server/api/endpoints/admin/reset-password.ts
index b6cf1ee2d0..1fd5c8d5a5 100644
--- a/packages/backend/src/server/api/endpoints/admin/reset-password.ts
+++ b/packages/backend/src/server/api/endpoints/admin/reset-password.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import * as bcrypt from 'bcryptjs';
+import define from '../../define.js';
+import bcrypt from 'bcryptjs';
 import rndstr from 'rndstr';
-import { Users, UserProfiles } from '@/models/index';
+import { Users, UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -11,12 +9,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -31,8 +23,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/resolve-abuse-user-report.ts b/packages/backend/src/server/api/endpoints/admin/resolve-abuse-user-report.ts
index a47b69ec1a..a9e5658413 100644
--- a/packages/backend/src/server/api/endpoints/admin/resolve-abuse-user-report.ts
+++ b/packages/backend/src/server/api/endpoints/admin/resolve-abuse-user-report.ts
@@ -1,33 +1,28 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { AbuseUserReports, Users } from '@/models/index';
-import { getInstanceActor } from '@/services/instance-actor';
-import { deliver } from '@/queue/index';
-import { renderActivity } from '@/remote/activitypub/renderer/index';
-import { renderFlag } from '@/remote/activitypub/renderer/flag';
+import define from '../../define.js';
+import { AbuseUserReports, Users } from '@/models/index.js';
+import { getInstanceActor } from '@/services/instance-actor.js';
+import { deliver } from '@/queue/index.js';
+import { renderActivity } from '@/remote/activitypub/renderer/index.js';
+import { renderFlag } from '@/remote/activitypub/renderer/flag.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		reportId: {
-			validator: $.type(ID),
-		},
-
-		forward: {
-			validator: $.optional.boolean,
-			required: false,
-			default: false,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		reportId: { type: 'string', format: 'misskey:id' },
+		forward: { type: 'boolean', default: false },
 	},
+	required: ['reportId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const report = await AbuseUserReports.findOne(ps.reportId);
 
 	if (report == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/send-email.ts b/packages/backend/src/server/api/endpoints/admin/send-email.ts
index c2972c35fa..bbdd66e4c9 100644
--- a/packages/backend/src/server/api/endpoints/admin/send-email.ts
+++ b/packages/backend/src/server/api/endpoints/admin/send-email.ts
@@ -1,27 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { sendEmail } from '@/services/send-email';
+import define from '../../define.js';
+import { sendEmail } from '@/services/send-email.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		to: {
-			validator: $.str,
-		},
-		subject: {
-			validator: $.str,
-		},
-		text: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		to: { type: 'string' },
+		subject: { type: 'string' },
+		text: { type: 'string' },
 	},
+	required: ['to', 'subject', 'text'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	await sendEmail(ps.to, ps.subject, ps.text, ps.text);
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/server-info.ts b/packages/backend/src/server/api/endpoints/admin/server-info.ts
index cd282e364c..8bf1c4341c 100644
--- a/packages/backend/src/server/api/endpoints/admin/server-info.ts
+++ b/packages/backend/src/server/api/endpoints/admin/server-info.ts
@@ -1,8 +1,8 @@
-import * as os from 'os';
-import * as si from 'systeminformation';
+import * as os from 'node:os';
+import si from 'systeminformation';
 import { getConnection } from 'typeorm';
-import define from '../../define';
-import { redisClient } from '../../../../db/redis';
+import define from '../../define.js';
+import { redisClient } from '../../../../db/redis.js';
 
 export const meta = {
 	requireCredential: true,
@@ -10,9 +10,6 @@ export const meta = {
 
 	tags: ['admin', 'meta'],
 
-	params: {
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -90,8 +87,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const memStats = await si.mem();
 	const fsStats = await si.fsSize();
 	const netInterface = await si.networkInterfaceDefault();
diff --git a/packages/backend/src/server/api/endpoints/admin/show-moderation-logs.ts b/packages/backend/src/server/api/endpoints/admin/show-moderation-logs.ts
index 84e2b84bb5..3545536aa2 100644
--- a/packages/backend/src/server/api/endpoints/admin/show-moderation-logs.ts
+++ b/packages/backend/src/server/api/endpoints/admin/show-moderation-logs.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ModerationLogs } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { ModerationLogs } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -10,21 +8,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -65,11 +48,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const query = makePaginationQuery(ModerationLogs.createQueryBuilder('report'), ps.sinceId, ps.untilId);
 
-	const reports = await query.take(ps.limit!).getMany();
+	const reports = await query.take(ps.limit).getMany();
 
 	return await ModerationLogs.packMany(reports);
 });
diff --git a/packages/backend/src/server/api/endpoints/admin/show-user.ts b/packages/backend/src/server/api/endpoints/admin/show-user.ts
index 0d0cc9087a..a435dcc288 100644
--- a/packages/backend/src/server/api/endpoints/admin/show-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/show-user.ts
@@ -1,7 +1,5 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Users } from '@/models/index';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -9,20 +7,22 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		nullable: false, optional: false,
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/show-users.ts b/packages/backend/src/server/api/endpoints/admin/show-users.ts
index d3dde99b72..1ec86fef2e 100644
--- a/packages/backend/src/server/api/endpoints/admin/show-users.ts
+++ b/packages/backend/src/server/api/endpoints/admin/show-users.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Users } from '@/models/index';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['admin'],
@@ -8,61 +7,6 @@ export const meta = {
 	requireCredential: true,
 	requireModerator: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-
-		sort: {
-			validator: $.optional.str.or([
-				'+follower',
-				'-follower',
-				'+createdAt',
-				'-createdAt',
-				'+updatedAt',
-				'-updatedAt',
-			]),
-		},
-
-		state: {
-			validator: $.optional.str.or([
-				'all',
-				'available',
-				'admin',
-				'moderator',
-				'adminOrModerator',
-				'silenced',
-				'suspended',
-			]),
-			default: 'all',
-		},
-
-		origin: {
-			validator: $.optional.str.or([
-				'combined',
-				'local',
-				'remote',
-			]),
-			default: 'local',
-		},
-
-		username: {
-			validator: $.optional.str,
-			default: null,
-		},
-
-		hostname: {
-			validator: $.optional.str,
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'array',
 		nullable: false, optional: false,
@@ -74,8 +18,22 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+		sort: { type: 'string', enum: ['+follower', '-follower', '+createdAt', '-createdAt', '+updatedAt', '-updatedAt'] },
+		state: { type: 'string', enum: ['all', 'available', 'admin', 'moderator', 'adminOrModerator', 'silenced', 'suspended'], default: "all" },
+		origin: { type: 'string', enum: ['combined', 'local', 'remote'], default: "local" },
+		username: { type: 'string', default: null },
+		hostname: { type: 'string', default: null },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Users.createQueryBuilder('user');
 
 	switch (ps.state) {
@@ -111,7 +69,7 @@ export default define(meta, async (ps, me) => {
 		default: query.orderBy('user.id', 'ASC'); break;
 	}
 
-	query.take(ps.limit!);
+	query.take(ps.limit);
 	query.skip(ps.offset);
 
 	const users = await query.getMany();
diff --git a/packages/backend/src/server/api/endpoints/admin/silence-user.ts b/packages/backend/src/server/api/endpoints/admin/silence-user.ts
index 872bd2a6ac..4a74c3fb00 100644
--- a/packages/backend/src/server/api/endpoints/admin/silence-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/silence-user.ts
@@ -1,24 +1,24 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Users } from '@/models/index';
-import { insertModerationLog } from '@/services/insert-moderation-log';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/suspend-user.ts b/packages/backend/src/server/api/endpoints/admin/suspend-user.ts
index 2bb1875fc0..adaa7b86ce 100644
--- a/packages/backend/src/server/api/endpoints/admin/suspend-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/suspend-user.ts
@@ -1,28 +1,28 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import deleteFollowing from '@/services/following/delete';
-import { Users, Followings, Notifications } from '@/models/index';
-import { User } from '@/models/entities/user';
-import { insertModerationLog } from '@/services/insert-moderation-log';
-import { doPostSuspend } from '@/services/suspend-user';
-import { publishUserEvent } from '@/services/stream';
+import define from '../../define.js';
+import deleteFollowing from '@/services/following/delete.js';
+import { Users, Followings, Notifications } from '@/models/index.js';
+import { User } from '@/models/entities/user.js';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
+import { doPostSuspend } from '@/services/suspend-user.js';
+import { publishUserEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/unsilence-user.ts b/packages/backend/src/server/api/endpoints/admin/unsilence-user.ts
index a4c6ff2ade..4e6366aa18 100644
--- a/packages/backend/src/server/api/endpoints/admin/unsilence-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/unsilence-user.ts
@@ -1,24 +1,24 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Users } from '@/models/index';
-import { insertModerationLog } from '@/services/insert-moderation-log';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/unsuspend-user.ts b/packages/backend/src/server/api/endpoints/admin/unsuspend-user.ts
index 5ab56d51c7..3b9e0a94e0 100644
--- a/packages/backend/src/server/api/endpoints/admin/unsuspend-user.ts
+++ b/packages/backend/src/server/api/endpoints/admin/unsuspend-user.ts
@@ -1,25 +1,25 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Users } from '@/models/index';
-import { insertModerationLog } from '@/services/insert-moderation-log';
-import { doPostUnsuspend } from '@/services/unsuspend-user';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
+import { doPostUnsuspend } from '@/services/unsuspend-user.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId as string);
 
 	if (user == null) {
diff --git a/packages/backend/src/server/api/endpoints/admin/update-meta.ts b/packages/backend/src/server/api/endpoints/admin/update-meta.ts
index 1764d230a3..66b634c877 100644
--- a/packages/backend/src/server/api/endpoints/admin/update-meta.ts
+++ b/packages/backend/src/server/api/endpoints/admin/update-meta.ts
@@ -1,310 +1,107 @@
-import $ from 'cafy';
-import define from '../../define';
+import define from '../../define.js';
 import { getConnection } from 'typeorm';
-import { Meta } from '@/models/entities/meta';
-import { insertModerationLog } from '@/services/insert-moderation-log';
-import { DB_MAX_NOTE_TEXT_LENGTH } from '@/misc/hard-limits';
-import { ID } from '@/misc/cafy-id';
+import { Meta } from '@/models/entities/meta.js';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
+import { DB_MAX_NOTE_TEXT_LENGTH } from '@/misc/hard-limits.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireAdmin: true,
+} as const;
 
-	params: {
-		disableRegistration: {
-			validator: $.optional.nullable.bool,
-		},
-
-		disableLocalTimeline: {
-			validator: $.optional.nullable.bool,
-		},
-
-		disableGlobalTimeline: {
-			validator: $.optional.nullable.bool,
-		},
-
-		useStarForReactionFallback: {
-			validator: $.optional.nullable.bool,
-		},
-
-		pinnedUsers: {
-			validator: $.optional.nullable.arr($.str),
-		},
-
-		hiddenTags: {
-			validator: $.optional.nullable.arr($.str),
-		},
-
-		blockedHosts: {
-			validator: $.optional.nullable.arr($.str),
-		},
-
-		themeColor: {
-			validator: $.optional.nullable.str,
-		},
-
-		mascotImageUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		bannerUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		errorImageUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		iconUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		backgroundImageUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		logoImageUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		name: {
-			validator: $.optional.nullable.str,
-		},
-
-		description: {
-			validator: $.optional.nullable.str,
-		},
-
-		maxNoteTextLength: {
-			validator: $.optional.num.min(0).max(DB_MAX_NOTE_TEXT_LENGTH),
-		},
-
-		localDriveCapacityMb: {
-			validator: $.optional.num.min(0),
-		},
-
-		remoteDriveCapacityMb: {
-			validator: $.optional.num.min(0),
-		},
-
-		cacheRemoteFiles: {
-			validator: $.optional.bool,
-		},
-
-		proxyRemoteFiles: {
-			validator: $.optional.bool,
-		},
-
-		emailRequiredForSignup: {
-			validator: $.optional.bool,
-		},
-
-		enableHcaptcha: {
-			validator: $.optional.bool,
-		},
-
-		hcaptchaSiteKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		hcaptchaSecretKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		enableRecaptcha: {
-			validator: $.optional.bool,
-		},
-
-		recaptchaSiteKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		recaptchaSecretKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		proxyAccountId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		maintainerName: {
-			validator: $.optional.nullable.str,
-		},
-
-		maintainerEmail: {
-			validator: $.optional.nullable.str,
-		},
-
-		pinnedPages: {
-			validator: $.optional.arr($.str),
-		},
-
-		pinnedClipId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		langs: {
-			validator: $.optional.arr($.str),
-		},
-
-		summalyProxy: {
-			validator: $.optional.nullable.str,
-		},
-
-		deeplAuthKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		deeplIsPro: {
-			validator: $.optional.bool,
-		},
-
-		enableTwitterIntegration: {
-			validator: $.optional.bool,
-		},
-
-		twitterConsumerKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		twitterConsumerSecret: {
-			validator: $.optional.nullable.str,
-		},
-
-		enableGithubIntegration: {
-			validator: $.optional.bool,
-		},
-
-		githubClientId: {
-			validator: $.optional.nullable.str,
-		},
-
-		githubClientSecret: {
-			validator: $.optional.nullable.str,
-		},
-
-		enableDiscordIntegration: {
-			validator: $.optional.bool,
-		},
-
-		discordClientId: {
-			validator: $.optional.nullable.str,
-		},
-
-		discordClientSecret: {
-			validator: $.optional.nullable.str,
-		},
-
-		enableEmail: {
-			validator: $.optional.bool,
-		},
-
-		email: {
-			validator: $.optional.nullable.str,
-		},
-
-		smtpSecure: {
-			validator: $.optional.bool,
-		},
-
-		smtpHost: {
-			validator: $.optional.nullable.str,
-		},
-
-		smtpPort: {
-			validator: $.optional.nullable.num,
-		},
-
-		smtpUser: {
-			validator: $.optional.nullable.str,
-		},
-
-		smtpPass: {
-			validator: $.optional.nullable.str,
-		},
-
-		enableServiceWorker: {
-			validator: $.optional.bool,
-		},
-
-		swPublicKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		swPrivateKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		tosUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		repositoryUrl: {
-			validator: $.optional.str,
-		},
-
-		feedbackUrl: {
-			validator: $.optional.str,
-		},
-
-		useObjectStorage: {
-			validator: $.optional.bool,
-		},
-
-		objectStorageBaseUrl: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStorageBucket: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStoragePrefix: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStorageEndpoint: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStorageRegion: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStoragePort: {
-			validator: $.optional.nullable.num,
-		},
-
-		objectStorageAccessKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStorageSecretKey: {
-			validator: $.optional.nullable.str,
-		},
-
-		objectStorageUseSSL: {
-			validator: $.optional.bool,
-		},
-
-		objectStorageUseProxy: {
-			validator: $.optional.bool,
-		},
-
-		objectStorageSetPublicRead: {
-			validator: $.optional.bool,
-		},
-
-		objectStorageS3ForcePathStyle: {
-			validator: $.optional.bool,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		disableRegistration: { type: 'boolean', nullable: true },
+		disableLocalTimeline: { type: 'boolean', nullable: true },
+		disableGlobalTimeline: { type: 'boolean', nullable: true },
+		useStarForReactionFallback: { type: 'boolean', nullable: true },
+		pinnedUsers: { type: 'array', nullable: true, items: {
+			type: 'string',
+		} },
+		hiddenTags: { type: 'array', nullable: true, items: {
+			type: 'string',
+		} },
+		blockedHosts: { type: 'array', nullable: true, items: {
+			type: 'string',
+		} },
+		themeColor: { type: 'string', nullable: true },
+		mascotImageUrl: { type: 'string', nullable: true },
+		bannerUrl: { type: 'string', nullable: true },
+		errorImageUrl: { type: 'string', nullable: true },
+		iconUrl: { type: 'string', nullable: true },
+		backgroundImageUrl: { type: 'string', nullable: true },
+		logoImageUrl: { type: 'string', nullable: true },
+		name: { type: 'string', nullable: true },
+		description: { type: 'string', nullable: true },
+		defaultLightTheme: { type: 'string', nullable: true },
+		defaultDarkTheme: { type: 'string', nullable: true },
+		localDriveCapacityMb: { type: 'integer' },
+		remoteDriveCapacityMb: { type: 'integer' },
+		cacheRemoteFiles: { type: 'boolean' },
+		emailRequiredForSignup: { type: 'boolean' },
+		enableHcaptcha: { type: 'boolean' },
+		hcaptchaSiteKey: { type: 'string', nullable: true },
+		hcaptchaSecretKey: { type: 'string', nullable: true },
+		enableRecaptcha: { type: 'boolean' },
+		recaptchaSiteKey: { type: 'string', nullable: true },
+		recaptchaSecretKey: { type: 'string', nullable: true },
+		proxyAccountId: { type: 'string', format: 'misskey:id', nullable: true },
+		maintainerName: { type: 'string', nullable: true },
+		maintainerEmail: { type: 'string', nullable: true },
+		pinnedPages: { type: 'array', items: {
+			type: 'string',
+		} },
+		pinnedClipId: { type: 'string', format: 'misskey:id', nullable: true },
+		langs: { type: 'array', items: {
+			type: 'string',
+		} },
+		summalyProxy: { type: 'string', nullable: true },
+		deeplAuthKey: { type: 'string', nullable: true },
+		deeplIsPro: { type: 'boolean' },
+		enableTwitterIntegration: { type: 'boolean' },
+		twitterConsumerKey: { type: 'string', nullable: true },
+		twitterConsumerSecret: { type: 'string', nullable: true },
+		enableGithubIntegration: { type: 'boolean' },
+		githubClientId: { type: 'string', nullable: true },
+		githubClientSecret: { type: 'string', nullable: true },
+		enableDiscordIntegration: { type: 'boolean' },
+		discordClientId: { type: 'string', nullable: true },
+		discordClientSecret: { type: 'string', nullable: true },
+		enableEmail: { type: 'boolean' },
+		email: { type: 'string', nullable: true },
+		smtpSecure: { type: 'boolean' },
+		smtpHost: { type: 'string', nullable: true },
+		smtpPort: { type: 'integer', nullable: true },
+		smtpUser: { type: 'string', nullable: true },
+		smtpPass: { type: 'string', nullable: true },
+		enableServiceWorker: { type: 'boolean' },
+		swPublicKey: { type: 'string', nullable: true },
+		swPrivateKey: { type: 'string', nullable: true },
+		tosUrl: { type: 'string', nullable: true },
+		repositoryUrl: { type: 'string' },
+		feedbackUrl: { type: 'string' },
+		useObjectStorage: { type: 'boolean' },
+		objectStorageBaseUrl: { type: 'string', nullable: true },
+		objectStorageBucket: { type: 'string', nullable: true },
+		objectStoragePrefix: { type: 'string', nullable: true },
+		objectStorageEndpoint: { type: 'string', nullable: true },
+		objectStorageRegion: { type: 'string', nullable: true },
+		objectStoragePort: { type: 'integer', nullable: true },
+		objectStorageAccessKey: { type: 'string', nullable: true },
+		objectStorageSecretKey: { type: 'string', nullable: true },
+		objectStorageUseSSL: { type: 'boolean' },
+		objectStorageUseProxy: { type: 'boolean' },
+		objectStorageSetPublicRead: { type: 'boolean' },
+		objectStorageS3ForcePathStyle: { type: 'boolean' },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const set = {} as Partial<Meta>;
 
 	if (typeof ps.disableRegistration === 'boolean') {
@@ -367,8 +164,12 @@ export default define(meta, async (ps, me) => {
 		set.description = ps.description;
 	}
 
-	if (ps.maxNoteTextLength) {
-		set.maxNoteTextLength = ps.maxNoteTextLength;
+	if (ps.defaultLightTheme !== undefined) {
+		set.defaultLightTheme = ps.defaultLightTheme;
+	}
+
+	if (ps.defaultDarkTheme !== undefined) {
+		set.defaultDarkTheme = ps.defaultDarkTheme;
 	}
 
 	if (ps.localDriveCapacityMb !== undefined) {
@@ -383,10 +184,6 @@ export default define(meta, async (ps, me) => {
 		set.cacheRemoteFiles = ps.cacheRemoteFiles;
 	}
 
-	if (ps.proxyRemoteFiles !== undefined) {
-		set.proxyRemoteFiles = ps.proxyRemoteFiles;
-	}
-
 	if (ps.emailRequiredForSignup !== undefined) {
 		set.emailRequiredForSignup = ps.emailRequiredForSignup;
 	}
diff --git a/packages/backend/src/server/api/endpoints/admin/vacuum.ts b/packages/backend/src/server/api/endpoints/admin/vacuum.ts
index 4229ef0d29..4c04e019da 100644
--- a/packages/backend/src/server/api/endpoints/admin/vacuum.ts
+++ b/packages/backend/src/server/api/endpoints/admin/vacuum.ts
@@ -1,26 +1,25 @@
-import $ from 'cafy';
-import define from '../../define';
+import define from '../../define.js';
 import { getConnection } from 'typeorm';
-import { insertModerationLog } from '@/services/insert-moderation-log';
+import { insertModerationLog } from '@/services/insert-moderation-log.js';
 
 export const meta = {
 	tags: ['admin'],
 
 	requireCredential: true,
 	requireModerator: true,
+} as const;
 
-	params: {
-		full: {
-			validator: $.bool,
-		},
-		analyze: {
-			validator: $.bool,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		full: { type: 'boolean' },
+		analyze: { type: 'boolean' },
 	},
+	required: ['full', 'analyze'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const params: string[] = [];
 
 	if (ps.full) {
diff --git a/packages/backend/src/server/api/endpoints/announcements.ts b/packages/backend/src/server/api/endpoints/announcements.ts
index 22c13743a8..bba66e98cf 100644
--- a/packages/backend/src/server/api/endpoints/announcements.ts
+++ b/packages/backend/src/server/api/endpoints/announcements.ts
@@ -1,34 +1,12 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../define';
-import { Announcements, AnnouncementReads } from '@/models/index';
-import { makePaginationQuery } from '../common/make-pagination-query';
+import define from '../define.js';
+import { Announcements, AnnouncementReads } from '@/models/index.js';
+import { makePaginationQuery } from '../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['meta'],
 
 	requireCredential: false,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		withUnreads: {
-			validator: $.optional.boolean,
-			default: false,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -73,11 +51,22 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		withUnreads: { type: 'boolean', default: false },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Announcements.createQueryBuilder('announcement'), ps.sinceId, ps.untilId);
 
-	const announcements = await query.take(ps.limit!).getMany();
+	const announcements = await query.take(ps.limit).getMany();
 
 	if (user) {
 		const reads = (await AnnouncementReads.find({
diff --git a/packages/backend/src/server/api/endpoints/antennas/create.ts b/packages/backend/src/server/api/endpoints/antennas/create.ts
index 2092d177ba..92cbba817e 100644
--- a/packages/backend/src/server/api/endpoints/antennas/create.ts
+++ b/packages/backend/src/server/api/endpoints/antennas/create.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import define from '../../define';
-import { genId } from '@/misc/gen-id';
-import { Antennas, UserLists, UserGroupJoinings } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
-import { ApiError } from '../../error';
-import { publishInternalEvent } from '@/services/stream';
+import define from '../../define.js';
+import { genId } from '@/misc/gen-id.js';
+import { Antennas, UserLists, UserGroupJoinings } from '@/models/index.js';
+import { ApiError } from '../../error.js';
+import { publishInternalEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['antennas'],
@@ -13,52 +11,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		name: {
-			validator: $.str.range(1, 100),
-		},
-
-		src: {
-			validator: $.str.or(['home', 'all', 'users', 'list', 'group']),
-		},
-
-		userListId: {
-			validator: $.nullable.optional.type(ID),
-		},
-
-		userGroupId: {
-			validator: $.nullable.optional.type(ID),
-		},
-
-		keywords: {
-			validator: $.arr($.arr($.str)),
-		},
-
-		excludeKeywords: {
-			validator: $.arr($.arr($.str)),
-		},
-
-		users: {
-			validator: $.arr($.str),
-		},
-
-		caseSensitive: {
-			validator: $.bool,
-		},
-
-		withReplies: {
-			validator: $.bool,
-		},
-
-		withFile: {
-			validator: $.bool,
-		},
-
-		notify: {
-			validator: $.bool,
-		},
-	},
-
 	errors: {
 		noSuchUserList: {
 			message: 'No such user list.',
@@ -80,8 +32,36 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+		src: { type: 'string', enum: ['home', 'all', 'users', 'list', 'group'] },
+		userListId: { type: 'string', format: 'misskey:id', nullable: true },
+		userGroupId: { type: 'string', format: 'misskey:id', nullable: true },
+		keywords: { type: 'array', items: {
+			type: 'array', items: {
+				type: 'string',
+			},
+		} },
+		excludeKeywords: { type: 'array', items: {
+			type: 'array', items: {
+				type: 'string',
+			},
+		} },
+		users: { type: 'array', items: {
+			type: 'string',
+		} },
+		caseSensitive: { type: 'boolean' },
+		withReplies: { type: 'boolean' },
+		withFile: { type: 'boolean' },
+		notify: { type: 'boolean' },
+	},
+	required: ['name', 'src', 'keywords', 'excludeKeywords', 'users', 'caseSensitive', 'withReplies', 'withFile', 'notify'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let userList;
 	let userGroupJoining;
 
diff --git a/packages/backend/src/server/api/endpoints/antennas/delete.ts b/packages/backend/src/server/api/endpoints/antennas/delete.ts
index b2793fc70d..4e6b8b3d2e 100644
--- a/packages/backend/src/server/api/endpoints/antennas/delete.ts
+++ b/packages/backend/src/server/api/endpoints/antennas/delete.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Antennas } from '@/models/index';
-import { publishInternalEvent } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Antennas } from '@/models/index.js';
+import { publishInternalEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['antennas'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		antennaId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchAntenna: {
 			message: 'No such antenna.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		antennaId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['antennaId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const antenna = await Antennas.findOne({
 		id: ps.antennaId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/antennas/list.ts b/packages/backend/src/server/api/endpoints/antennas/list.ts
index bb58912612..accca5de76 100644
--- a/packages/backend/src/server/api/endpoints/antennas/list.ts
+++ b/packages/backend/src/server/api/endpoints/antennas/list.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { Antennas } from '@/models/index';
+import define from '../../define.js';
+import { Antennas } from '@/models/index.js';
 
 export const meta = {
 	tags: ['antennas', 'account'],
@@ -19,8 +19,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const antennas = await Antennas.find({
 		userId: me.id,
 	});
diff --git a/packages/backend/src/server/api/endpoints/antennas/notes.ts b/packages/backend/src/server/api/endpoints/antennas/notes.ts
index eb7de901c5..f0cb2ba3c0 100644
--- a/packages/backend/src/server/api/endpoints/antennas/notes.ts
+++ b/packages/backend/src/server/api/endpoints/antennas/notes.ts
@@ -1,13 +1,11 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import readNote from '@/services/note/read';
-import { Antennas, Notes, AntennaNotes } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { ApiError } from '../../error';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import define from '../../define.js';
+import readNote from '@/services/note/read.js';
+import { Antennas, Notes, AntennaNotes } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { ApiError } from '../../error.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['antennas', 'account', 'notes'],
@@ -16,33 +14,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-		antennaId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-	},
-
 	errors: {
 		noSuchAntenna: {
 			message: 'No such antenna.',
@@ -62,8 +33,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		antennaId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+	},
+	required: ['antennaId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const antenna = await Antennas.findOne({
 		id: ps.antennaId,
 		userId: user.id,
@@ -81,10 +65,16 @@ export default define(meta, async (ps, user) => {
 			ps.sinceId, ps.untilId, ps.sinceDate, ps.untilDate)
 		.andWhere(`note.id IN (${ antennaQuery.getQuery() })`)
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
 		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner')
 		.setParameters(antennaQuery.getParameters());
 
 	generateVisibilityQuery(query, user);
@@ -92,7 +82,7 @@ export default define(meta, async (ps, user) => {
 	generateBlockedUserQuery(query, user);
 
 	const notes = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	if (notes.length > 0) {
diff --git a/packages/backend/src/server/api/endpoints/antennas/show.ts b/packages/backend/src/server/api/endpoints/antennas/show.ts
index a37d37d31c..36c4da81b7 100644
--- a/packages/backend/src/server/api/endpoints/antennas/show.ts
+++ b/packages/backend/src/server/api/endpoints/antennas/show.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Antennas } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Antennas } from '@/models/index.js';
 
 export const meta = {
 	tags: ['antennas', 'account'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-		antennaId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchAntenna: {
 			message: 'No such antenna.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		antennaId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['antennaId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the antenna
 	const antenna = await Antennas.findOne({
 		id: ps.antennaId,
diff --git a/packages/backend/src/server/api/endpoints/antennas/update.ts b/packages/backend/src/server/api/endpoints/antennas/update.ts
index 900f725505..a99964555b 100644
--- a/packages/backend/src/server/api/endpoints/antennas/update.ts
+++ b/packages/backend/src/server/api/endpoints/antennas/update.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Antennas, UserLists, UserGroupJoinings } from '@/models/index';
-import { publishInternalEvent } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Antennas, UserLists, UserGroupJoinings } from '@/models/index.js';
+import { publishInternalEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['antennas'],
@@ -12,56 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		antennaId: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.str.range(1, 100),
-		},
-
-		src: {
-			validator: $.str.or(['home', 'all', 'users', 'list', 'group']),
-		},
-
-		userListId: {
-			validator: $.nullable.optional.type(ID),
-		},
-
-		userGroupId: {
-			validator: $.nullable.optional.type(ID),
-		},
-
-		keywords: {
-			validator: $.arr($.arr($.str)),
-		},
-
-		excludeKeywords: {
-			validator: $.arr($.arr($.str)),
-		},
-
-		users: {
-			validator: $.arr($.str),
-		},
-
-		caseSensitive: {
-			validator: $.bool,
-		},
-
-		withReplies: {
-			validator: $.bool,
-		},
-
-		withFile: {
-			validator: $.bool,
-		},
-
-		notify: {
-			validator: $.bool,
-		},
-	},
-
 	errors: {
 		noSuchAntenna: {
 			message: 'No such antenna.',
@@ -89,8 +37,37 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		antennaId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+		src: { type: 'string', enum: ['home', 'all', 'users', 'list', 'group'] },
+		userListId: { type: 'string', format: 'misskey:id', nullable: true },
+		userGroupId: { type: 'string', format: 'misskey:id', nullable: true },
+		keywords: { type: 'array', items: {
+			type: 'array', items: {
+				type: 'string',
+			},
+		} },
+		excludeKeywords: { type: 'array', items: {
+			type: 'array', items: {
+				type: 'string',
+			},
+		} },
+		users: { type: 'array', items: {
+			type: 'string',
+		} },
+		caseSensitive: { type: 'boolean' },
+		withReplies: { type: 'boolean' },
+		withFile: { type: 'boolean' },
+		notify: { type: 'boolean' },
+	},
+	required: ['antennaId', 'name', 'src', 'keywords', 'excludeKeywords', 'users', 'caseSensitive', 'withReplies', 'withFile', 'notify'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch the antenna
 	const antenna = await Antennas.findOne({
 		id: ps.antennaId,
diff --git a/packages/backend/src/server/api/endpoints/ap/get.ts b/packages/backend/src/server/api/endpoints/ap/get.ts
index ff8c677b91..0cbe7ebc67 100644
--- a/packages/backend/src/server/api/endpoints/ap/get.ts
+++ b/packages/backend/src/server/api/endpoints/ap/get.ts
@@ -1,7 +1,6 @@
-import $ from 'cafy';
-import define from '../../define';
-import Resolver from '@/remote/activitypub/resolver';
-import { ApiError } from '../../error';
+import define from '../../define.js';
+import Resolver from '@/remote/activitypub/resolver.js';
+import { ApiError } from '../../error.js';
 import ms from 'ms';
 
 export const meta = {
@@ -14,12 +13,6 @@ export const meta = {
 		max: 30,
 	},
 
-	params: {
-		uri: {
-			validator: $.str,
-		},
-	},
-
 	errors: {
 	},
 
@@ -29,8 +22,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		uri: { type: 'string' },
+	},
+	required: ['uri'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const resolver = new Resolver();
 	const object = await resolver.resolve(ps.uri);
 	return object;
diff --git a/packages/backend/src/server/api/endpoints/ap/show.ts b/packages/backend/src/server/api/endpoints/ap/show.ts
index 7d17d8edce..7595c38e8a 100644
--- a/packages/backend/src/server/api/endpoints/ap/show.ts
+++ b/packages/backend/src/server/api/endpoints/ap/show.ts
@@ -1,18 +1,17 @@
-import $ from 'cafy';
-import define from '../../define';
-import config from '@/config/index';
-import { createPerson } from '@/remote/activitypub/models/person';
-import { createNote } from '@/remote/activitypub/models/note';
-import Resolver from '@/remote/activitypub/resolver';
-import { ApiError } from '../../error';
-import { extractDbHost } from '@/misc/convert-host';
-import { Users, Notes } from '@/models/index';
-import { Note } from '@/models/entities/note';
-import { User } from '@/models/entities/user';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { isActor, isPost, getApId } from '@/remote/activitypub/type';
+import define from '../../define.js';
+import config from '@/config/index.js';
+import { createPerson } from '@/remote/activitypub/models/person.js';
+import { createNote } from '@/remote/activitypub/models/note.js';
+import Resolver from '@/remote/activitypub/resolver.js';
+import { ApiError } from '../../error.js';
+import { extractDbHost } from '@/misc/convert-host.js';
+import { Users, Notes } from '@/models/index.js';
+import { Note } from '@/models/entities/note.js';
+import { User } from '@/models/entities/user.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { isActor, isPost, getApId } from '@/remote/activitypub/type.js';
 import ms from 'ms';
-import { SchemaType } from '@/misc/schema';
+import { SchemaType } from '@/misc/schema.js';
 
 export const meta = {
 	tags: ['federation'],
@@ -24,12 +23,6 @@ export const meta = {
 		max: 30,
 	},
 
-	params: {
-		uri: {
-			validator: $.str,
-		},
-	},
-
 	errors: {
 		noSuchObject: {
 			message: 'No such object.',
@@ -75,8 +68,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		uri: { type: 'string' },
+	},
+	required: ['uri'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const object = await fetchAny(ps.uri);
 	if (object) {
 		return object;
diff --git a/packages/backend/src/server/api/endpoints/app/create.ts b/packages/backend/src/server/api/endpoints/app/create.ts
index fbe6690f1d..e0cf8632fb 100644
--- a/packages/backend/src/server/api/endpoints/app/create.ts
+++ b/packages/backend/src/server/api/endpoints/app/create.ts
@@ -1,35 +1,14 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Apps } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { unique } from '@/prelude/array';
-import { secureRndstr } from '@/misc/secure-rndstr';
+import define from '../../define.js';
+import { Apps } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { unique } from '@/prelude/array.js';
+import { secureRndstr } from '@/misc/secure-rndstr.js';
 
 export const meta = {
 	tags: ['app'],
 
 	requireCredential: false,
 
-	params: {
-		name: {
-			validator: $.str,
-		},
-
-		description: {
-			validator: $.str,
-		},
-
-		permission: {
-			validator: $.arr($.str).unique(),
-		},
-
-		// TODO: Check it is valid url
-		callbackUrl: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -37,8 +16,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string' },
+		description: { type: 'string' },
+		permission: { type: 'array', uniqueItems: true, items: {
+			type: 'string',
+		} },
+		callbackUrl: { type: 'string', nullable: true },
+	},
+	required: ['name', 'description', 'permission'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Generate secret
 	const secret = secureRndstr(32, true);
 
diff --git a/packages/backend/src/server/api/endpoints/app/show.ts b/packages/backend/src/server/api/endpoints/app/show.ts
index 9f4777b383..54e714e193 100644
--- a/packages/backend/src/server/api/endpoints/app/show.ts
+++ b/packages/backend/src/server/api/endpoints/app/show.ts
@@ -1,18 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Apps } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Apps } from '@/models/index.js';
 
 export const meta = {
 	tags: ['app'],
 
-	params: {
-		appId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchApp: {
 			message: 'No such app.',
@@ -28,8 +20,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		appId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['appId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user, token) => {
+export default define(meta, paramDef, async (ps, user, token) => {
 	const isSecure = user != null && token == null;
 
 	// Lookup app
diff --git a/packages/backend/src/server/api/endpoints/auth/accept.ts b/packages/backend/src/server/api/endpoints/auth/accept.ts
index f028135ca5..0760eef52b 100644
--- a/packages/backend/src/server/api/endpoints/auth/accept.ts
+++ b/packages/backend/src/server/api/endpoints/auth/accept.ts
@@ -1,10 +1,9 @@
-import * as crypto from 'crypto';
-import $ from 'cafy';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { AuthSessions, AccessTokens, Apps } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { secureRndstr } from '@/misc/secure-rndstr';
+import * as crypto from 'node:crypto';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { AuthSessions, AccessTokens, Apps } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { secureRndstr } from '@/misc/secure-rndstr.js';
 
 export const meta = {
 	tags: ['auth'],
@@ -13,12 +12,6 @@ export const meta = {
 
 	secure: true,
 
-	params: {
-		token: {
-			validator: $.str,
-		},
-	},
-
 	errors: {
 		noSuchSession: {
 			message: 'No such session.',
@@ -28,8 +21,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		token: { type: 'string' },
+	},
+	required: ['token'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch token
 	const session = await AuthSessions
 		.findOne({ token: ps.token });
diff --git a/packages/backend/src/server/api/endpoints/auth/session/generate.ts b/packages/backend/src/server/api/endpoints/auth/session/generate.ts
index 98987eba5b..bd571327d2 100644
--- a/packages/backend/src/server/api/endpoints/auth/session/generate.ts
+++ b/packages/backend/src/server/api/endpoints/auth/session/generate.ts
@@ -1,22 +1,15 @@
 import { v4 as uuid } from 'uuid';
-import $ from 'cafy';
-import config from '@/config/index';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { Apps, AuthSessions } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import config from '@/config/index.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { Apps, AuthSessions } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['auth'],
 
 	requireCredential: false,
 
-	params: {
-		appSecret: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -42,8 +35,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		appSecret: { type: 'string' },
+	},
+	required: ['appSecret'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	// Lookup app
 	const app = await Apps.findOne({
 		secret: ps.appSecret,
diff --git a/packages/backend/src/server/api/endpoints/auth/session/show.ts b/packages/backend/src/server/api/endpoints/auth/session/show.ts
index ae0d016cea..d40c9363c6 100644
--- a/packages/backend/src/server/api/endpoints/auth/session/show.ts
+++ b/packages/backend/src/server/api/endpoints/auth/session/show.ts
@@ -1,19 +1,12 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { AuthSessions } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { AuthSessions } from '@/models/index.js';
 
 export const meta = {
 	tags: ['auth'],
 
 	requireCredential: false,
 
-	params: {
-		token: {
-			validator: $.str,
-		},
-	},
-
 	errors: {
 		noSuchSession: {
 			message: 'No such session.',
@@ -44,8 +37,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		token: { type: 'string' },
+	},
+	required: ['token'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Lookup session
 	const session = await AuthSessions.findOne({
 		token: ps.token,
diff --git a/packages/backend/src/server/api/endpoints/auth/session/userkey.ts b/packages/backend/src/server/api/endpoints/auth/session/userkey.ts
index fe0211ebe3..b699c6fa25 100644
--- a/packages/backend/src/server/api/endpoints/auth/session/userkey.ts
+++ b/packages/backend/src/server/api/endpoints/auth/session/userkey.ts
@@ -1,23 +1,12 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { Apps, AuthSessions, AccessTokens, Users } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { Apps, AuthSessions, AccessTokens, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['auth'],
 
 	requireCredential: false,
 
-	params: {
-		appSecret: {
-			validator: $.str,
-		},
-
-		token: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -56,8 +45,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		appSecret: { type: 'string' },
+		token: { type: 'string' },
+	},
+	required: ['appSecret', 'token'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	// Lookup app
 	const app = await Apps.findOne({
 		secret: ps.appSecret,
diff --git a/packages/backend/src/server/api/endpoints/blocking/create.ts b/packages/backend/src/server/api/endpoints/blocking/create.ts
index 6d555ff569..c5e73c0131 100644
--- a/packages/backend/src/server/api/endpoints/blocking/create.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/create.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
 import ms from 'ms';
-import create from '@/services/blocking/create';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { Blockings, NoteWatchings, Users } from '@/models/index';
+import create from '@/services/blocking/create.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { Blockings, NoteWatchings, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
@@ -19,12 +17,6 @@ export const meta = {
 
 	kind: 'write:blocks',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -52,8 +44,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const blocker = await Users.findOneOrFail(user.id);
 
 	// 自分自身
diff --git a/packages/backend/src/server/api/endpoints/blocking/delete.ts b/packages/backend/src/server/api/endpoints/blocking/delete.ts
index 942cddaedf..a45547290c 100644
--- a/packages/backend/src/server/api/endpoints/blocking/delete.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/delete.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
 import ms from 'ms';
-import deleteBlocking from '@/services/blocking/delete';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { Blockings, Users } from '@/models/index';
+import deleteBlocking from '@/services/blocking/delete.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { Blockings, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
@@ -19,12 +17,6 @@ export const meta = {
 
 	kind: 'write:blocks',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -52,8 +44,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const blocker = await Users.findOneOrFail(user.id);
 
 	// Check if the blockee is yourself
diff --git a/packages/backend/src/server/api/endpoints/blocking/list.ts b/packages/backend/src/server/api/endpoints/blocking/list.ts
index 9a4f662140..29095ebe21 100644
--- a/packages/backend/src/server/api/endpoints/blocking/list.ts
+++ b/packages/backend/src/server/api/endpoints/blocking/list.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Blockings } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Blockings } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:blocks',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 30,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,13 +20,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 30 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Blockings.createQueryBuilder('blocking'), ps.sinceId, ps.untilId)
 		.andWhere(`blocking.blockerId = :meId`, { meId: me.id });
 
 	const blockings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Blockings.packMany(blockings, me);
diff --git a/packages/backend/src/server/api/endpoints/channels/create.ts b/packages/backend/src/server/api/endpoints/channels/create.ts
index 68cdf1143e..16456b9c01 100644
--- a/packages/backend/src/server/api/endpoints/channels/create.ts
+++ b/packages/backend/src/server/api/endpoints/channels/create.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Channels, DriveFiles } from '@/models/index';
-import { Channel } from '@/models/entities/channel';
-import { genId } from '@/misc/gen-id';
-import { ID } from '@/misc/cafy-id';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Channels, DriveFiles } from '@/models/index.js';
+import { Channel } from '@/models/entities/channel.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['channels'],
@@ -13,20 +11,6 @@ export const meta = {
 
 	kind: 'write:channels',
 
-	params: {
-		name: {
-			validator: $.str.range(1, 128),
-		},
-
-		description: {
-			validator: $.nullable.optional.str.range(1, 2048),
-		},
-
-		bannerId: {
-			validator: $.nullable.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -42,8 +26,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string', minLength: 1, maxLength: 128 },
+		description: { type: 'string', nullable: true, minLength: 1, maxLength: 2048 },
+		bannerId: { type: 'string', format: 'misskey:id', nullable: true },
+	},
+	required: ['name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let banner = null;
 	if (ps.bannerId != null) {
 		banner = await DriveFiles.findOne({
diff --git a/packages/backend/src/server/api/endpoints/channels/featured.ts b/packages/backend/src/server/api/endpoints/channels/featured.ts
index ceadde907c..73980c0fad 100644
--- a/packages/backend/src/server/api/endpoints/channels/featured.ts
+++ b/packages/backend/src/server/api/endpoints/channels/featured.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { Channels } from '@/models/index';
+import define from '../../define.js';
+import { Channels } from '@/models/index.js';
 
 export const meta = {
 	tags: ['channels'],
@@ -17,8 +17,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Channels.createQueryBuilder('channel')
 		.where('channel.lastNotedAt IS NOT NULL')
 		.orderBy('channel.lastNotedAt', 'DESC');
diff --git a/packages/backend/src/server/api/endpoints/channels/follow.ts b/packages/backend/src/server/api/endpoints/channels/follow.ts
index bf580eea60..4372c283cb 100644
--- a/packages/backend/src/server/api/endpoints/channels/follow.ts
+++ b/packages/backend/src/server/api/endpoints/channels/follow.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Channels, ChannelFollowings } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { publishUserEvent } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Channels, ChannelFollowings } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { publishUserEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['channels'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:channels',
 
-	params: {
-		channelId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchChannel: {
 			message: 'No such channel.',
@@ -28,8 +20,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		channelId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['channelId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const channel = await Channels.findOne({
 		id: ps.channelId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/channels/followed.ts b/packages/backend/src/server/api/endpoints/channels/followed.ts
index 9e4c942af2..e4aa4d1614 100644
--- a/packages/backend/src/server/api/endpoints/channels/followed.ts
+++ b/packages/backend/src/server/api/endpoints/channels/followed.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Channels, ChannelFollowings } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Channels, ChannelFollowings } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['channels', 'account'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:channels',
 
-	params: {
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 5,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,13 +20,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 5 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(ChannelFollowings.createQueryBuilder(), ps.sinceId, ps.untilId)
 		.andWhere({ followerId: me.id });
 
 	const followings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Promise.all(followings.map(x => Channels.pack(x.followeeId, me)));
diff --git a/packages/backend/src/server/api/endpoints/channels/owned.ts b/packages/backend/src/server/api/endpoints/channels/owned.ts
index 5473636a85..ed7e41cac2 100644
--- a/packages/backend/src/server/api/endpoints/channels/owned.ts
+++ b/packages/backend/src/server/api/endpoints/channels/owned.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Channels } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Channels } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['channels', 'account'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:channels',
 
-	params: {
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 5,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,13 +20,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 5 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Channels.createQueryBuilder(), ps.sinceId, ps.untilId)
 		.andWhere({ userId: me.id });
 
 	const channels = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Promise.all(channels.map(x => Channels.pack(x, me)));
diff --git a/packages/backend/src/server/api/endpoints/channels/show.ts b/packages/backend/src/server/api/endpoints/channels/show.ts
index 598a87ec4e..ea4e013073 100644
--- a/packages/backend/src/server/api/endpoints/channels/show.ts
+++ b/packages/backend/src/server/api/endpoints/channels/show.ts
@@ -1,20 +1,12 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Channels } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Channels } from '@/models/index.js';
 
 export const meta = {
 	tags: ['channels'],
 
 	requireCredential: false,
 
-	params: {
-		channelId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -30,8 +22,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		channelId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['channelId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const channel = await Channels.findOne({
 		id: ps.channelId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/channels/timeline.ts b/packages/backend/src/server/api/endpoints/channels/timeline.ts
index 2639095f8a..57a9fa44b8 100644
--- a/packages/backend/src/server/api/endpoints/channels/timeline.ts
+++ b/packages/backend/src/server/api/endpoints/channels/timeline.ts
@@ -1,43 +1,14 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Notes, Channels } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { activeUsersChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Notes, Channels } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { activeUsersChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['notes', 'channels'],
 
 	requireCredential: false,
 
-	params: {
-		channelId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -57,8 +28,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		channelId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+	},
+	required: ['channelId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const channel = await Channels.findOne({
 		id: ps.channelId,
 	});
@@ -71,14 +55,20 @@ export default define(meta, async (ps, user) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId, ps.sinceDate, ps.untilDate)
 		.andWhere('note.channelId = :channelId', { channelId: channel.id })
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
 		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner')
 		.leftJoinAndSelect('note.channel', 'channel');
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	if (user) activeUsersChart.read(user);
 
diff --git a/packages/backend/src/server/api/endpoints/channels/unfollow.ts b/packages/backend/src/server/api/endpoints/channels/unfollow.ts
index ada0cb29fd..32beb24d6f 100644
--- a/packages/backend/src/server/api/endpoints/channels/unfollow.ts
+++ b/packages/backend/src/server/api/endpoints/channels/unfollow.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Channels, ChannelFollowings } from '@/models/index';
-import { publishUserEvent } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Channels, ChannelFollowings } from '@/models/index.js';
+import { publishUserEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['channels'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:channels',
 
-	params: {
-		channelId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchChannel: {
 			message: 'No such channel.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		channelId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['channelId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const channel = await Channels.findOne({
 		id: ps.channelId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/channels/update.ts b/packages/backend/src/server/api/endpoints/channels/update.ts
index 1f7108a1cb..2f2b4aeeb2 100644
--- a/packages/backend/src/server/api/endpoints/channels/update.ts
+++ b/packages/backend/src/server/api/endpoints/channels/update.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Channels, DriveFiles } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Channels, DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['channels'],
@@ -11,24 +9,6 @@ export const meta = {
 
 	kind: 'write:channels',
 
-	params: {
-		channelId: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.optional.str.range(1, 128),
-		},
-
-		description: {
-			validator: $.nullable.optional.str.range(1, 2048),
-		},
-
-		bannerId: {
-			validator: $.nullable.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -56,8 +36,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		channelId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string', minLength: 1, maxLength: 128 },
+		description: { type: 'string', nullable: true, minLength: 1, maxLength: 2048 },
+		bannerId: { type: 'string', format: 'misskey:id', nullable: true },
+	},
+	required: ['channelId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const channel = await Channels.findOne({
 		id: ps.channelId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/charts/active-users.ts b/packages/backend/src/server/api/endpoints/charts/active-users.ts
index a51cd00351..97f7885dbe 100644
--- a/packages/backend/src/server/api/endpoints/charts/active-users.ts
+++ b/packages/backend/src/server/api/endpoints/charts/active-users.ts
@@ -1,31 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { activeUsersChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { activeUsersChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'users'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
+	res: getJsonSchema(activeUsersChart.schema),
+} as const;
 
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
 	},
-
-	// TODO: response definition
+	required: ['span'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await activeUsersChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null);
+export default define(meta, paramDef, async (ps) => {
+	return await activeUsersChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/ap-request.ts b/packages/backend/src/server/api/endpoints/charts/ap-request.ts
index 38bbddb27a..4477bfc987 100644
--- a/packages/backend/src/server/api/endpoints/charts/ap-request.ts
+++ b/packages/backend/src/server/api/endpoints/charts/ap-request.ts
@@ -1,31 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { apRequestChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { apRequestChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
+	res: getJsonSchema(apRequestChart.schema),
+} as const;
 
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
 	},
-
-	// TODO: response definition
+	required: ['span'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await apRequestChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null);
+export default define(meta, paramDef, async (ps) => {
+	return await apRequestChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/drive.ts b/packages/backend/src/server/api/endpoints/charts/drive.ts
index 4bbb9861f8..fd6033392f 100644
--- a/packages/backend/src/server/api/endpoints/charts/drive.ts
+++ b/packages/backend/src/server/api/endpoints/charts/drive.ts
@@ -1,31 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { driveChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { driveChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'drive'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
+	res: getJsonSchema(driveChart.schema),
+} as const;
 
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
 	},
-
-	// TODO: response definition
+	required: ['span'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await driveChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null);
+export default define(meta, paramDef, async (ps) => {
+	return await driveChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/federation.ts b/packages/backend/src/server/api/endpoints/charts/federation.ts
index 237678ffed..f842f574ec 100644
--- a/packages/backend/src/server/api/endpoints/charts/federation.ts
+++ b/packages/backend/src/server/api/endpoints/charts/federation.ts
@@ -1,31 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { federationChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { federationChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
+	res: getJsonSchema(federationChart.schema),
+} as const;
 
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
 	},
-
-	// TODO: response definition
+	required: ['span'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await federationChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null);
+export default define(meta, paramDef, async (ps) => {
+	return await federationChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/hashtag.ts b/packages/backend/src/server/api/endpoints/charts/hashtag.ts
index 6c12cb063e..01407defdd 100644
--- a/packages/backend/src/server/api/endpoints/charts/hashtag.ts
+++ b/packages/backend/src/server/api/endpoints/charts/hashtag.ts
@@ -1,35 +1,25 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { hashtagChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { hashtagChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'hashtags'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+	res: getJsonSchema(hashtagChart.schema),
+} as const;
 
-		tag: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
+		tag: { type: 'string' },
 	},
-
-	// TODO: response definition
+	required: ['span', 'tag'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await hashtagChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null, ps.tag);
+export default define(meta, paramDef, async (ps) => {
+	return await hashtagChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null, ps.tag);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/instance.ts b/packages/backend/src/server/api/endpoints/charts/instance.ts
index 32a10d5a28..2d12951c6c 100644
--- a/packages/backend/src/server/api/endpoints/charts/instance.ts
+++ b/packages/backend/src/server/api/endpoints/charts/instance.ts
@@ -1,35 +1,25 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { instanceChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { instanceChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+	res: getJsonSchema(instanceChart.schema),
+} as const;
 
-		host: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
+		host: { type: 'string' },
 	},
-
-	// TODO: response definition
+	required: ['span', 'host'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await instanceChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null, ps.host);
+export default define(meta, paramDef, async (ps) => {
+	return await instanceChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null, ps.host);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/notes.ts b/packages/backend/src/server/api/endpoints/charts/notes.ts
index 09255f1d2d..b6089f67ef 100644
--- a/packages/backend/src/server/api/endpoints/charts/notes.ts
+++ b/packages/backend/src/server/api/endpoints/charts/notes.ts
@@ -1,31 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { notesChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { notesChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'notes'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
+	res: getJsonSchema(notesChart.schema),
+} as const;
 
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
 	},
-
-	// TODO: response definition
+	required: ['span'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await notesChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null);
+export default define(meta, paramDef, async (ps) => {
+	return await notesChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/user/drive.ts b/packages/backend/src/server/api/endpoints/charts/user/drive.ts
index 89379858d1..e5db7131a8 100644
--- a/packages/backend/src/server/api/endpoints/charts/user/drive.ts
+++ b/packages/backend/src/server/api/endpoints/charts/user/drive.ts
@@ -1,36 +1,25 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { convertLog } from '@/services/chart/core';
-import { perUserDriveChart } from '@/services/chart/index';
+import define from '../../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { perUserDriveChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'drive', 'users'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+	res: getJsonSchema(perUserDriveChart.schema),
+} as const;
 
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
+		userId: { type: 'string', format: 'misskey:id' },
 	},
-
-	// TODO: response definition
+	required: ['span', 'userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await perUserDriveChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null, ps.userId);
+export default define(meta, paramDef, async (ps) => {
+	return await perUserDriveChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null, ps.userId);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/user/following.ts b/packages/backend/src/server/api/endpoints/charts/user/following.ts
index 26c3f5c126..9b72de745d 100644
--- a/packages/backend/src/server/api/endpoints/charts/user/following.ts
+++ b/packages/backend/src/server/api/endpoints/charts/user/following.ts
@@ -1,36 +1,25 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { convertLog } from '@/services/chart/core';
-import { perUserFollowingChart } from '@/services/chart/index';
+import define from '../../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { perUserFollowingChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'users', 'following'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+	res: getJsonSchema(perUserFollowingChart.schema),
+} as const;
 
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
+		userId: { type: 'string', format: 'misskey:id' },
 	},
-
-	// TODO: response definition
+	required: ['span', 'userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await perUserFollowingChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null, ps.userId);
+export default define(meta, paramDef, async (ps) => {
+	return await perUserFollowingChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null, ps.userId);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/user/notes.ts b/packages/backend/src/server/api/endpoints/charts/user/notes.ts
index ecf85becfa..7cc6cbf316 100644
--- a/packages/backend/src/server/api/endpoints/charts/user/notes.ts
+++ b/packages/backend/src/server/api/endpoints/charts/user/notes.ts
@@ -1,36 +1,25 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { convertLog } from '@/services/chart/core';
-import { perUserNotesChart } from '@/services/chart/index';
+import define from '../../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { perUserNotesChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'users', 'notes'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+	res: getJsonSchema(perUserNotesChart.schema),
+} as const;
 
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
+		userId: { type: 'string', format: 'misskey:id' },
 	},
-
-	// TODO: response definition
+	required: ['span', 'userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await perUserNotesChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null, ps.userId);
+export default define(meta, paramDef, async (ps) => {
+	return await perUserNotesChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null, ps.userId);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/user/reactions.ts b/packages/backend/src/server/api/endpoints/charts/user/reactions.ts
index 6e08d07511..5c58a7f152 100644
--- a/packages/backend/src/server/api/endpoints/charts/user/reactions.ts
+++ b/packages/backend/src/server/api/endpoints/charts/user/reactions.ts
@@ -1,36 +1,25 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ID } from '@/misc/cafy-id';
-import { convertLog } from '@/services/chart/core';
-import { perUserReactionsChart } from '@/services/chart/index';
+import define from '../../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { perUserReactionsChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'users', 'reactions'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+	res: getJsonSchema(perUserReactionsChart.schema),
+} as const;
 
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
+		userId: { type: 'string', format: 'misskey:id' },
 	},
-
-	// TODO: response definition
+	required: ['span', 'userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await perUserReactionsChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null, ps.userId);
+export default define(meta, paramDef, async (ps) => {
+	return await perUserReactionsChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null, ps.userId);
 });
diff --git a/packages/backend/src/server/api/endpoints/charts/users.ts b/packages/backend/src/server/api/endpoints/charts/users.ts
index 15a9ec038e..49c762b2e4 100644
--- a/packages/backend/src/server/api/endpoints/charts/users.ts
+++ b/packages/backend/src/server/api/endpoints/charts/users.ts
@@ -1,31 +1,24 @@
-import $ from 'cafy';
-import define from '../../define';
-import { convertLog } from '@/services/chart/core';
-import { usersChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { getJsonSchema } from '@/services/chart/core.js';
+import { usersChart } from '@/services/chart/index.js';
 
 export const meta = {
 	tags: ['charts', 'users'],
 
-	params: {
-		span: {
-			validator: $.str.or(['day', 'hour']),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 500),
-			default: 30,
-		},
+	res: getJsonSchema(usersChart.schema),
+} as const;
 
-		offset: {
-			validator: $.optional.nullable.num,
-			default: null,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		span: { type: 'string', enum: ['day', 'hour'] },
+		limit: { type: 'integer', minimum: 1, maximum: 500, default: 30 },
+		offset: { type: 'integer', nullable: true, default: null },
 	},
-
-	// TODO: response definition
+	required: ['span'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
-	return await usersChart.getChart(ps.span as any, ps.limit!, ps.offset ? new Date(ps.offset) : null);
+export default define(meta, paramDef, async (ps) => {
+	return await usersChart.getChart(ps.span, ps.limit, ps.offset ? new Date(ps.offset) : null);
 });
diff --git a/packages/backend/src/server/api/endpoints/clips/add-note.ts b/packages/backend/src/server/api/endpoints/clips/add-note.ts
index 4a740b6cfe..c630302b98 100644
--- a/packages/backend/src/server/api/endpoints/clips/add-note.ts
+++ b/packages/backend/src/server/api/endpoints/clips/add-note.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ClipNotes, Clips } from '@/models/index';
-import { ApiError } from '../../error';
-import { genId } from '@/misc/gen-id';
-import { getNote } from '../../common/getters';
+import define from '../../define.js';
+import { ClipNotes, Clips } from '@/models/index.js';
+import { ApiError } from '../../error.js';
+import { genId } from '@/misc/gen-id.js';
+import { getNote } from '../../common/getters.js';
 
 export const meta = {
 	tags: ['account', 'notes', 'clips'],
@@ -13,16 +11,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		clipId: {
-			validator: $.type(ID),
-		},
-
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchClip: {
 			message: 'No such clip.',
@@ -44,8 +32,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		clipId: { type: 'string', format: 'misskey:id' },
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['clipId', 'noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const clip = await Clips.findOne({
 		id: ps.clipId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/clips/create.ts b/packages/backend/src/server/api/endpoints/clips/create.ts
index 852e66c9e4..531847d15c 100644
--- a/packages/backend/src/server/api/endpoints/clips/create.ts
+++ b/packages/backend/src/server/api/endpoints/clips/create.ts
@@ -1,7 +1,6 @@
-import $ from 'cafy';
-import define from '../../define';
-import { genId } from '@/misc/gen-id';
-import { Clips } from '@/models/index';
+import define from '../../define.js';
+import { genId } from '@/misc/gen-id.js';
+import { Clips } from '@/models/index.js';
 
 export const meta = {
 	tags: ['clips'],
@@ -10,20 +9,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		name: {
-			validator: $.str.range(1, 100),
-		},
-
-		isPublic: {
-			validator: $.optional.bool,
-		},
-
-		description: {
-			validator: $.optional.nullable.str.range(1, 2048),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -31,8 +16,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+		isPublic: { type: 'boolean' },
+		description: { type: 'string', nullable: true, minLength: 1, maxLength: 2048 },
+	},
+	required: ['name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const clip = await Clips.insert({
 		id: genId(),
 		createdAt: new Date(),
diff --git a/packages/backend/src/server/api/endpoints/clips/delete.ts b/packages/backend/src/server/api/endpoints/clips/delete.ts
index 85c64a115d..675db1d57f 100644
--- a/packages/backend/src/server/api/endpoints/clips/delete.ts
+++ b/packages/backend/src/server/api/endpoints/clips/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Clips } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Clips } from '@/models/index.js';
 
 export const meta = {
 	tags: ['clips'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		clipId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchClip: {
 			message: 'No such clip.',
@@ -26,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		clipId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['clipId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const clip = await Clips.findOne({
 		id: ps.clipId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/clips/list.ts b/packages/backend/src/server/api/endpoints/clips/list.ts
index d88897d164..1c955d64fc 100644
--- a/packages/backend/src/server/api/endpoints/clips/list.ts
+++ b/packages/backend/src/server/api/endpoints/clips/list.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { Clips } from '@/models/index';
+import define from '../../define.js';
+import { Clips } from '@/models/index.js';
 
 export const meta = {
 	tags: ['clips', 'account'],
@@ -19,8 +19,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const clips = await Clips.find({
 		userId: me.id,
 	});
diff --git a/packages/backend/src/server/api/endpoints/clips/notes.ts b/packages/backend/src/server/api/endpoints/clips/notes.ts
index eeb20631c1..2627884ee1 100644
--- a/packages/backend/src/server/api/endpoints/clips/notes.ts
+++ b/packages/backend/src/server/api/endpoints/clips/notes.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ClipNotes, Clips, Notes } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { ApiError } from '../../error';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import define from '../../define.js';
+import { ClipNotes, Clips, Notes } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { ApiError } from '../../error.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['account', 'notes', 'clips'],
@@ -15,25 +13,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-		clipId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchClip: {
 			message: 'No such clip.',
@@ -53,8 +32,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		clipId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['clipId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const clip = await Clips.findOne({
 		id: ps.clipId,
 	});
@@ -74,10 +64,16 @@ export default define(meta, async (ps, user) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.andWhere(`note.id IN (${ clipQuery.getQuery() })`)
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
 		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner')
 		.setParameters(clipQuery.getParameters());
 
 	if (user) {
@@ -87,7 +83,7 @@ export default define(meta, async (ps, user) => {
 	}
 
 	const notes = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Notes.packMany(notes, user);
diff --git a/packages/backend/src/server/api/endpoints/clips/show.ts b/packages/backend/src/server/api/endpoints/clips/show.ts
index 0a45672019..0a3b25c94e 100644
--- a/packages/backend/src/server/api/endpoints/clips/show.ts
+++ b/packages/backend/src/server/api/endpoints/clips/show.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Clips } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Clips } from '@/models/index.js';
 
 export const meta = {
 	tags: ['clips', 'account'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-		clipId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchClip: {
 			message: 'No such clip.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		clipId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['clipId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the clip
 	const clip = await Clips.findOne({
 		id: ps.clipId,
diff --git a/packages/backend/src/server/api/endpoints/clips/update.ts b/packages/backend/src/server/api/endpoints/clips/update.ts
index 795483d5b2..0ac5ccd047 100644
--- a/packages/backend/src/server/api/endpoints/clips/update.ts
+++ b/packages/backend/src/server/api/endpoints/clips/update.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Clips } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Clips } from '@/models/index.js';
 
 export const meta = {
 	tags: ['clips'],
@@ -11,24 +9,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		clipId: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.str.range(1, 100),
-		},
-
-		isPublic: {
-			validator: $.optional.bool,
-		},
-
-		description: {
-			validator: $.optional.nullable.str.range(1, 2048),
-		},
-	},
-
 	errors: {
 		noSuchClip: {
 			message: 'No such clip.',
@@ -44,8 +24,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		clipId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+		isPublic: { type: 'boolean' },
+		description: { type: 'string', nullable: true, minLength: 1, maxLength: 2048 },
+	},
+	required: ['clipId', 'name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch the clip
 	const clip = await Clips.findOne({
 		id: ps.clipId,
diff --git a/packages/backend/src/server/api/endpoints/drive.ts b/packages/backend/src/server/api/endpoints/drive.ts
index d9ab9883ca..c599d96ca4 100644
--- a/packages/backend/src/server/api/endpoints/drive.ts
+++ b/packages/backend/src/server/api/endpoints/drive.ts
@@ -1,6 +1,6 @@
-import define from '../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { DriveFiles } from '@/models/index';
+import define from '../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive', 'account'],
@@ -25,8 +25,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const instance = await fetchMeta(true);
 
 	// Calculate drive usage
diff --git a/packages/backend/src/server/api/endpoints/drive/files.ts b/packages/backend/src/server/api/endpoints/drive/files.ts
index a5c0a626a1..40e6c16c9c 100644
--- a/packages/backend/src/server/api/endpoints/drive/files.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { DriveFiles } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { DriveFiles } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -11,30 +9,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		folderId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-
-		type: {
-			validator: $.optional.nullable.str.match(/^[a-zA-Z\/\-*]+$/),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -46,8 +20,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		folderId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+		type: { type: 'string', nullable: true, pattern: /^[a-zA-Z\/\-*]+$/.toString().slice(1, -1) },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(DriveFiles.createQueryBuilder('file'), ps.sinceId, ps.untilId)
 		.andWhere('file.userId = :userId', { userId: user.id });
 
@@ -65,7 +51,7 @@ export default define(meta, async (ps, user) => {
 		}
 	}
 
-	const files = await query.take(ps.limit!).getMany();
+	const files = await query.take(ps.limit).getMany();
 
 	return await DriveFiles.packMany(files, { detail: false, self: true });
 });
diff --git a/packages/backend/src/server/api/endpoints/drive/files/attached-notes.ts b/packages/backend/src/server/api/endpoints/drive/files/attached-notes.ts
index 835dde8058..3c68beee17 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/attached-notes.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/attached-notes.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFiles, Notes } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFiles, Notes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive', 'notes'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -36,8 +28,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch file
 	const file = await DriveFiles.findOne({
 		id: ps.fileId,
diff --git a/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts b/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts
index a45d357ee8..7e5cb2498e 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/check-existence.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -9,20 +8,22 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		md5: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'boolean',
 		optional: false, nullable: false,
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		md5: { type: 'string' },
+	},
+	required: ['md5'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne({
 		md5: ps.md5,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/drive/files/create.ts b/packages/backend/src/server/api/endpoints/drive/files/create.ts
index ac7863ec7e..b6a2cf7200 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/create.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/create.ts
@@ -1,12 +1,10 @@
 import ms from 'ms';
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { addFile } from '@/services/drive/add-file';
-import define from '../../../define';
-import { apiLogger } from '../../../logger';
-import { ApiError } from '../../../error';
-import { DriveFiles } from '@/models/index';
-import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits';
+import { addFile } from '@/services/drive/add-file.js';
+import define from '../../../define.js';
+import { apiLogger } from '../../../logger.js';
+import { ApiError } from '../../../error.js';
+import { DriveFiles } from '@/models/index.js';
+import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -22,33 +20,6 @@ export const meta = {
 
 	kind: 'write:drive',
 
-	params: {
-		folderId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-
-		name: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-
-		comment: {
-			validator: $.optional.nullable.str.max(DB_MAX_IMAGE_COMMENT_LENGTH),
-			default: null,
-		},
-
-		isSensitive: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		force: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -64,8 +35,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		folderId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+		name: { type: 'string', nullable: true, default: null },
+		comment: { type: 'string', nullable: true, maxLength: DB_MAX_IMAGE_COMMENT_LENGTH, default: null },
+		isSensitive: { type: 'boolean', default: false },
+		force: { type: 'boolean', default: false },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user, _, file, cleanup) => {
+// @ts-ignore
+export default define(meta, paramDef, async (ps, user, _, file, cleanup) => {
 	// Get 'name' parameter
 	let name = ps.name || file.originalname;
 	if (name !== undefined && name !== null) {
diff --git a/packages/backend/src/server/api/endpoints/drive/files/delete.ts b/packages/backend/src/server/api/endpoints/drive/files/delete.ts
index 308beb58a4..5f565a63fb 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/delete.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/delete.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { deleteFile } from '@/services/drive/delete-file';
-import { publishDriveStream } from '@/services/stream';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFiles } from '@/models/index';
+import { deleteFile } from '@/services/drive/delete-file.js';
+import { publishDriveStream } from '@/services/stream.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:drive',
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -34,8 +26,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) {
diff --git a/packages/backend/src/server/api/endpoints/drive/files/find-by-hash.ts b/packages/backend/src/server/api/endpoints/drive/files/find-by-hash.ts
index dc74dcb7e6..e45ec633d3 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/find-by-hash.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/find-by-hash.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -9,12 +8,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		md5: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -26,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		md5: { type: 'string' },
+	},
+	required: ['md5'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const files = await DriveFiles.find({
 		md5: ps.md5,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/drive/files/find.ts b/packages/backend/src/server/api/endpoints/drive/files/find.ts
index 2244df13cd..974fc9fbad 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/find.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/find.ts
@@ -1,7 +1,5 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
@@ -10,17 +8,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		name: {
-			validator: $.str,
-		},
-
-		folderId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -32,8 +19,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string' },
+		folderId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+	},
+	required: ['name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const files = await DriveFiles.find({
 		name: ps.name,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/drive/files/show.ts b/packages/backend/src/server/api/endpoints/drive/files/show.ts
index 18b17c4653..181365c7e6 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/show.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/show.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFile } from '@/models/entities/drive-file';
-import { DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFile } from '@/models/entities/drive-file.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -12,16 +10,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		fileId: {
-			validator: $.optional.type(ID),
-		},
-
-		url: {
-			validator: $.optional.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -49,8 +37,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+		url: { type: 'string' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let file: DriveFile | undefined;
 
 	if (ps.fileId) {
diff --git a/packages/backend/src/server/api/endpoints/drive/files/update.ts b/packages/backend/src/server/api/endpoints/drive/files/update.ts
index b7ca80e83c..ab8e4aeeb2 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/update.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/update.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { publishDriveStream } from '@/services/stream';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFiles, DriveFolders } from '@/models/index';
-import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits';
+import { publishDriveStream } from '@/services/stream.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFiles, DriveFolders } from '@/models/index.js';
+import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -13,33 +11,13 @@ export const meta = {
 
 	kind: 'write:drive',
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-
-		folderId: {
-			validator: $.optional.nullable.type(ID),
-			default: undefined as any,
-		},
-
-		name: {
-			validator: $.optional.str.pipe(DriveFiles.validateFileName),
-			default: undefined as any,
-		},
-
-		isSensitive: {
-			validator: $.optional.bool,
-			default: undefined as any,
-		},
-
-		comment: {
-			validator: $.optional.nullable.str.max(DB_MAX_IMAGE_COMMENT_LENGTH),
-			default: undefined as any,
+	errors: {
+		invalidFileName: {
+			message: 'Invalid file name.',
+			code: 'INVALID_FILE_NAME',
+			id: '395e7156-f9f0-475e-af89-53c3c23080c2',
 		},
-	},
 
-	errors: {
 		noSuchFile: {
 			message: 'No such file.',
 			code: 'NO_SUCH_FILE',
@@ -66,8 +44,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+		folderId: { type: 'string', format: 'misskey:id', nullable: true },
+		name: { type: 'string' },
+		isSensitive: { type: 'boolean' },
+		comment: { type: 'string', nullable: true, maxLength: 512 },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) {
@@ -79,6 +69,9 @@ export default define(meta, async (ps, user) => {
 	}
 
 	if (ps.name) file.name = ps.name;
+	if (!DriveFiles.validateFileName(file.name)) {
+		throw new ApiError(meta.errors.invalidFileName);
+	}
 
 	if (ps.comment !== undefined) file.comment = ps.comment;
 
diff --git a/packages/backend/src/server/api/endpoints/drive/files/upload-from-url.ts b/packages/backend/src/server/api/endpoints/drive/files/upload-from-url.ts
index 40da1a4fb4..3bfecac802 100644
--- a/packages/backend/src/server/api/endpoints/drive/files/upload-from-url.ts
+++ b/packages/backend/src/server/api/endpoints/drive/files/upload-from-url.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
 import ms from 'ms';
-import { uploadFromUrl } from '@/services/drive/upload-from-url';
-import define from '../../../define';
-import { DriveFiles } from '@/models/index';
-import { publishMainStream } from '@/services/stream';
-import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits';
+import { uploadFromUrl } from '@/services/drive/upload-from-url.js';
+import define from '../../../define.js';
+import { DriveFiles } from '@/models/index.js';
+import { publishMainStream } from '@/services/stream.js';
+import { DB_MAX_IMAGE_COMMENT_LENGTH } from '@/misc/hard-limits.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -18,42 +16,23 @@ export const meta = {
 	requireCredential: true,
 
 	kind: 'write:drive',
+} as const;
 
-	params: {
-		url: {
-			// TODO: Validate this url
-			validator: $.str,
-		},
-
-		folderId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-
-		isSensitive: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		comment: {
-			validator: $.optional.nullable.str.max(DB_MAX_IMAGE_COMMENT_LENGTH),
-			default: null,
-		},
-
-		marker: {
-			validator: $.optional.nullable.str,
-			default: null,
-		},
-
-		force: {
-			validator: $.optional.bool,
-			default: false,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		url: { type: 'string' },
+		folderId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+		isSensitive: { type: 'boolean', default: false },
+		comment: { type: 'string', nullable: true, maxLength: 512, default: null },
+		marker: { type: 'string', nullable: true, default: null },
+		force: { type: 'boolean', default: false },
 	},
+	required: ['url'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	uploadFromUrl({ url: ps.url, user, folderId: ps.folderId, sensitive: ps.isSensitive, force: ps.force, comment: ps.comment }).then(file => {
 		DriveFiles.pack(file, { self: true }).then(packedFile => {
 			publishMainStream(user.id, 'urlUploadFinished', {
diff --git a/packages/backend/src/server/api/endpoints/drive/folders.ts b/packages/backend/src/server/api/endpoints/drive/folders.ts
index 8f8d1d2c0a..d4d530ba9e 100644
--- a/packages/backend/src/server/api/endpoints/drive/folders.ts
+++ b/packages/backend/src/server/api/endpoints/drive/folders.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { DriveFolders } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { DriveFolders } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -11,26 +9,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		folderId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -42,8 +20,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		folderId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(DriveFolders.createQueryBuilder('folder'), ps.sinceId, ps.untilId)
 		.andWhere('folder.userId = :userId', { userId: user.id });
 
@@ -53,7 +42,7 @@ export default define(meta, async (ps, user) => {
 		query.andWhere('folder.parentId IS NULL');
 	}
 
-	const folders = await query.take(ps.limit!).getMany();
+	const folders = await query.take(ps.limit).getMany();
 
 	return await Promise.all(folders.map(folder => DriveFolders.pack(folder)));
 });
diff --git a/packages/backend/src/server/api/endpoints/drive/folders/create.ts b/packages/backend/src/server/api/endpoints/drive/folders/create.ts
index 38ed17e0e5..4ae10f0621 100644
--- a/packages/backend/src/server/api/endpoints/drive/folders/create.ts
+++ b/packages/backend/src/server/api/endpoints/drive/folders/create.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { publishDriveStream } from '@/services/stream';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFolders } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import { publishDriveStream } from '@/services/stream.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFolders } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -13,17 +11,6 @@ export const meta = {
 
 	kind: 'write:drive',
 
-	params: {
-		name: {
-			validator: $.optional.str.pipe(DriveFolders.validateFolderName),
-			default: 'Untitled',
-		},
-
-		parentId: {
-			validator: $.optional.nullable.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFolder: {
 			message: 'No such folder.',
@@ -39,8 +26,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string', default: "Untitled", maxLength: 200 },
+		parentId: { type: 'string', format: 'misskey:id', nullable: true },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// If the parent folder is specified
 	let parent = null;
 	if (ps.parentId) {
diff --git a/packages/backend/src/server/api/endpoints/drive/folders/delete.ts b/packages/backend/src/server/api/endpoints/drive/folders/delete.ts
index 13716fccea..4994615cc6 100644
--- a/packages/backend/src/server/api/endpoints/drive/folders/delete.ts
+++ b/packages/backend/src/server/api/endpoints/drive/folders/delete.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { publishDriveStream } from '@/services/stream';
-import { ApiError } from '../../../error';
-import { DriveFolders, DriveFiles } from '@/models/index';
+import define from '../../../define.js';
+import { publishDriveStream } from '@/services/stream.js';
+import { ApiError } from '../../../error.js';
+import { DriveFolders, DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:drive',
 
-	params: {
-		folderId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFolder: {
 			message: 'No such folder.',
@@ -33,8 +25,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		folderId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['folderId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Get folder
 	const folder = await DriveFolders.findOne({
 		id: ps.folderId,
diff --git a/packages/backend/src/server/api/endpoints/drive/folders/find.ts b/packages/backend/src/server/api/endpoints/drive/folders/find.ts
index 911f51d78b..9bf0e3d61b 100644
--- a/packages/backend/src/server/api/endpoints/drive/folders/find.ts
+++ b/packages/backend/src/server/api/endpoints/drive/folders/find.ts
@@ -1,7 +1,5 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { DriveFolders } from '@/models/index';
+import define from '../../../define.js';
+import { DriveFolders } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -10,17 +8,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		name: {
-			validator: $.str,
-		},
-
-		parentId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -32,8 +19,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string' },
+		parentId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+	},
+	required: ['name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const folders = await DriveFolders.find({
 		name: ps.name,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/drive/folders/show.ts b/packages/backend/src/server/api/endpoints/drive/folders/show.ts
index 58a6dd3c06..f09816d57a 100644
--- a/packages/backend/src/server/api/endpoints/drive/folders/show.ts
+++ b/packages/backend/src/server/api/endpoints/drive/folders/show.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFolders } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFolders } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		folderId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		folderId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['folderId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Get folder
 	const folder = await DriveFolders.findOne({
 		id: ps.folderId,
diff --git a/packages/backend/src/server/api/endpoints/drive/folders/update.ts b/packages/backend/src/server/api/endpoints/drive/folders/update.ts
index 5b0cccd1c6..c020b243ef 100644
--- a/packages/backend/src/server/api/endpoints/drive/folders/update.ts
+++ b/packages/backend/src/server/api/endpoints/drive/folders/update.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { publishDriveStream } from '@/services/stream';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { DriveFolders } from '@/models/index';
+import { publishDriveStream } from '@/services/stream.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { DriveFolders } from '@/models/index.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -12,20 +10,6 @@ export const meta = {
 
 	kind: 'write:drive',
 
-	params: {
-		folderId: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.optional.str.pipe(DriveFolders.validateFolderName),
-		},
-
-		parentId: {
-			validator: $.optional.nullable.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFolder: {
 			message: 'No such folder.',
@@ -53,8 +37,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		folderId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string', maxLength: 200 },
+		parentId: { type: 'string', format: 'misskey:id', nullable: true },
+	},
+	required: ['folderId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch folder
 	const folder = await DriveFolders.findOne({
 		id: ps.folderId,
diff --git a/packages/backend/src/server/api/endpoints/drive/stream.ts b/packages/backend/src/server/api/endpoints/drive/stream.ts
index 9ba7804946..99e8d024fb 100644
--- a/packages/backend/src/server/api/endpoints/drive/stream.ts
+++ b/packages/backend/src/server/api/endpoints/drive/stream.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { DriveFiles } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { DriveFiles } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['drive'],
@@ -11,25 +9,6 @@ export const meta = {
 
 	kind: 'read:drive',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		type: {
-			validator: $.optional.str.match(/^[a-zA-Z\/\-*]+$/),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -41,8 +20,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		type: { type: 'string', pattern: /^[a-zA-Z\/\-*]+$/.toString().slice(1, -1) },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(DriveFiles.createQueryBuilder('file'), ps.sinceId, ps.untilId)
 		.andWhere('file.userId = :userId', { userId: user.id });
 
@@ -54,7 +44,7 @@ export default define(meta, async (ps, user) => {
 		}
 	}
 
-	const files = await query.take(ps.limit!).getMany();
+	const files = await query.take(ps.limit).getMany();
 
 	return await DriveFiles.packMany(files, { detail: false, self: true });
 });
diff --git a/packages/backend/src/server/api/endpoints/email-address/available.ts b/packages/backend/src/server/api/endpoints/email-address/available.ts
index 19f9b7ccdc..07064ce9fa 100644
--- a/packages/backend/src/server/api/endpoints/email-address/available.ts
+++ b/packages/backend/src/server/api/endpoints/email-address/available.ts
@@ -1,18 +1,11 @@
-import $ from 'cafy';
-import define from '../../define';
-import { validateEmailForAccount } from '@/services/validate-email-for-account';
+import define from '../../define.js';
+import { validateEmailForAccount } from '@/services/validate-email-for-account.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		emailAddress: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -29,7 +22,15 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		emailAddress: { type: 'string' },
+	},
+	required: ['emailAddress'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	return await validateEmailForAccount(ps.emailAddress);
 });
diff --git a/packages/backend/src/server/api/endpoints/endpoint.ts b/packages/backend/src/server/api/endpoints/endpoint.ts
index 42fd468838..9db140183c 100644
--- a/packages/backend/src/server/api/endpoints/endpoint.ts
+++ b/packages/backend/src/server/api/endpoints/endpoint.ts
@@ -1,21 +1,22 @@
-import $ from 'cafy';
-import define from '../define';
-import endpoints from '../endpoints';
+import define from '../define.js';
+import endpoints from '../endpoints.js';
 
 export const meta = {
 	requireCredential: false,
 
 	tags: ['meta'],
+} as const;
 
-	params: {
-		endpoint: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		endpoint: { type: 'string' },
 	},
+	required: ['endpoint'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const ep = endpoints.find(x => x.name === ps.endpoint);
 	if (ep == null) return null;
 	return {
diff --git a/packages/backend/src/server/api/endpoints/endpoints.ts b/packages/backend/src/server/api/endpoints/endpoints.ts
index ebb78de337..b20da96eb3 100644
--- a/packages/backend/src/server/api/endpoints/endpoints.ts
+++ b/packages/backend/src/server/api/endpoints/endpoints.ts
@@ -1,14 +1,11 @@
-import define from '../define';
-import endpoints from '../endpoints';
+import define from '../define.js';
+import endpoints from '../endpoints.js';
 
 export const meta = {
 	requireCredential: false,
 
 	tags: ['meta'],
 
-	params: {
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -25,7 +22,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	return endpoints.map(x => x.name);
 });
diff --git a/packages/backend/src/server/api/endpoints/export-custom-emojis.ts b/packages/backend/src/server/api/endpoints/export-custom-emojis.ts
index 24c9f56aa6..bc8d2e2ac0 100644
--- a/packages/backend/src/server/api/endpoints/export-custom-emojis.ts
+++ b/packages/backend/src/server/api/endpoints/export-custom-emojis.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../define';
-import { createExportCustomEmojisJob } from '@/queue/index';
+import define from '../define.js';
+import { createExportCustomEmojisJob } from '@/queue/index.js';
 import ms from 'ms';
 
 export const meta = {
@@ -12,7 +11,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createExportCustomEmojisJob(user);
 });
diff --git a/packages/backend/src/server/api/endpoints/federation/followers.ts b/packages/backend/src/server/api/endpoints/federation/followers.ts
index c0a85f166c..7b1197d1e5 100644
--- a/packages/backend/src/server/api/endpoints/federation/followers.ts
+++ b/packages/backend/src/server/api/endpoints/federation/followers.ts
@@ -1,33 +1,12 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Followings } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Followings } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['federation'],
 
 	requireCredential: false,
 
-	params: {
-		host: {
-			validator: $.str,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -39,13 +18,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: ['host'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Followings.createQueryBuilder('following'), ps.sinceId, ps.untilId)
 		.andWhere(`following.followeeHost = :host`, { host: ps.host });
 
 	const followings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Followings.packMany(followings, me, { populateFollowee: true });
diff --git a/packages/backend/src/server/api/endpoints/federation/following.ts b/packages/backend/src/server/api/endpoints/federation/following.ts
index 147f0aedb2..ed1f142d88 100644
--- a/packages/backend/src/server/api/endpoints/federation/following.ts
+++ b/packages/backend/src/server/api/endpoints/federation/following.ts
@@ -1,33 +1,12 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Followings } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Followings } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['federation'],
 
 	requireCredential: false,
 
-	params: {
-		host: {
-			validator: $.str,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -39,13 +18,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: ['host'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Followings.createQueryBuilder('following'), ps.sinceId, ps.untilId)
 		.andWhere(`following.followerHost = :host`, { host: ps.host });
 
 	const followings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Followings.packMany(followings, me, { populateFollowee: true });
diff --git a/packages/backend/src/server/api/endpoints/federation/instances.ts b/packages/backend/src/server/api/endpoints/federation/instances.ts
index 11df7ed6b6..e272971763 100644
--- a/packages/backend/src/server/api/endpoints/federation/instances.ts
+++ b/packages/backend/src/server/api/endpoints/federation/instances.ts
@@ -1,58 +1,13 @@
-import $ from 'cafy';
-import config from '@/config/index';
-import define from '../../define';
-import { Instances } from '@/models/index';
-import { fetchMeta } from '@/misc/fetch-meta';
+import config from '@/config/index.js';
+import define from '../../define.js';
+import { Instances } from '@/models/index.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
 
 export const meta = {
 	tags: ['federation'],
 
 	requireCredential: false,
 
-	params: {
-		host: {
-			validator: $.optional.nullable.str,
-		},
-
-		blocked: {
-			validator: $.optional.nullable.bool,
-		},
-
-		notResponding: {
-			validator: $.optional.nullable.bool,
-		},
-
-		suspended: {
-			validator: $.optional.nullable.bool,
-		},
-
-		federating: {
-			validator: $.optional.nullable.bool,
-		},
-
-		subscribing: {
-			validator: $.optional.nullable.bool,
-		},
-
-		publishing: {
-			validator: $.optional.nullable.bool,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 30,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-
-		sort: {
-			validator: $.optional.str,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -64,8 +19,25 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string', nullable: true },
+		blocked: { type: 'boolean', nullable: true },
+		notResponding: { type: 'boolean', nullable: true },
+		suspended: { type: 'boolean', nullable: true },
+		federating: { type: 'boolean', nullable: true },
+		subscribing: { type: 'boolean', nullable: true },
+		publishing: { type: 'boolean', nullable: true },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 30 },
+		offset: { type: 'integer', default: 0 },
+		sort: { type: 'string' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Instances.createQueryBuilder('instance');
 
 	switch (ps.sort) {
@@ -83,10 +55,6 @@ export default define(meta, async (ps, me) => {
 		case '-caughtAt': query.orderBy('instance.caughtAt', 'ASC'); break;
 		case '+lastCommunicatedAt': query.orderBy('instance.lastCommunicatedAt', 'DESC'); break;
 		case '-lastCommunicatedAt': query.orderBy('instance.lastCommunicatedAt', 'ASC'); break;
-		case '+driveUsage': query.orderBy('instance.driveUsage', 'DESC'); break;
-		case '-driveUsage': query.orderBy('instance.driveUsage', 'ASC'); break;
-		case '+driveFiles': query.orderBy('instance.driveFiles', 'DESC'); break;
-		case '-driveFiles': query.orderBy('instance.driveFiles', 'ASC'); break;
 
 		default: query.orderBy('instance.id', 'DESC'); break;
 	}
@@ -144,7 +112,7 @@ export default define(meta, async (ps, me) => {
 		query.andWhere('instance.host like :host', { host: '%' + ps.host.toLowerCase() + '%' });
 	}
 
-	const instances = await query.take(ps.limit!).skip(ps.offset).getMany();
+	const instances = await query.take(ps.limit).skip(ps.offset).getMany();
 
-	return instances;
+	return await Instances.packMany(instances);
 });
diff --git a/packages/backend/src/server/api/endpoints/federation/show-instance.ts b/packages/backend/src/server/api/endpoints/federation/show-instance.ts
index 6f13b28cae..5bfe43fc9c 100644
--- a/packages/backend/src/server/api/endpoints/federation/show-instance.ts
+++ b/packages/backend/src/server/api/endpoints/federation/show-instance.ts
@@ -1,30 +1,34 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Instances } from '@/models/index';
-import { toPuny } from '@/misc/convert-host';
+import define from '../../define.js';
+import { Instances } from '@/models/index.js';
+import { toPuny } from '@/misc/convert-host.js';
 
 export const meta = {
 	tags: ['federation'],
 
 	requireCredential: false,
 
-	params: {
-		host: {
-			validator: $.str,
-		},
+	res: {
+		oneOf: [{
+			type: 'object',
+			ref: 'FederationInstance',
+		}, {
+			type: 'null',
+		}],
 	},
+} as const;
 
-	res: {
-		type: 'object',
-		optional: true, nullable: false,
-		ref: 'FederationInstance',
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
 	},
+	required: ['host'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const instance = await Instances
 		.findOne({ host: toPuny(ps.host) });
 
-	return instance;
+	return instance ? await Instances.pack(instance) : null;
 });
diff --git a/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts b/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts
index 092f805bc2..409cc7695e 100644
--- a/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts
+++ b/packages/backend/src/server/api/endpoints/federation/update-remote-user.ts
@@ -1,23 +1,23 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { getRemoteUser } from '../../common/getters';
-import { updatePerson } from '@/remote/activitypub/models/person';
+import define from '../../define.js';
+import { getRemoteUser } from '../../common/getters.js';
+import { updatePerson } from '@/remote/activitypub/models/person.js';
 
 export const meta = {
 	tags: ['federation'],
 
 	requireCredential: true,
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const user = await getRemoteUser(ps.userId);
 	await updatePerson(user.uri!);
 });
diff --git a/packages/backend/src/server/api/endpoints/federation/users.ts b/packages/backend/src/server/api/endpoints/federation/users.ts
index 9a8f749936..65ad9f88d3 100644
--- a/packages/backend/src/server/api/endpoints/federation/users.ts
+++ b/packages/backend/src/server/api/endpoints/federation/users.ts
@@ -1,33 +1,12 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Users } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['federation'],
 
 	requireCredential: false,
 
-	params: {
-		host: {
-			validator: $.str,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -39,13 +18,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		host: { type: 'string' },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: ['host'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Users.createQueryBuilder('user'), ps.sinceId, ps.untilId)
 		.andWhere(`user.host = :host`, { host: ps.host });
 
 	const users = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Users.packMany(users, me, { detail: true });
diff --git a/packages/backend/src/server/api/endpoints/following/create.ts b/packages/backend/src/server/api/endpoints/following/create.ts
index b840ab7696..8758a64a39 100644
--- a/packages/backend/src/server/api/endpoints/following/create.ts
+++ b/packages/backend/src/server/api/endpoints/following/create.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
 import ms from 'ms';
-import create from '@/services/following/create';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { Followings, Users } from '@/models/index';
-import { IdentifiableError } from '@/misc/identifiable-error';
+import create from '@/services/following/create.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { Followings, Users } from '@/models/index.js';
+import { IdentifiableError } from '@/misc/identifiable-error.js';
 
 export const meta = {
 	tags: ['following', 'users'],
@@ -20,12 +18,6 @@ export const meta = {
 
 	kind: 'write:following',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -65,8 +57,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const follower = user;
 
 	// 自分自身
diff --git a/packages/backend/src/server/api/endpoints/following/delete.ts b/packages/backend/src/server/api/endpoints/following/delete.ts
index 4cd0c49452..47efc59b81 100644
--- a/packages/backend/src/server/api/endpoints/following/delete.ts
+++ b/packages/backend/src/server/api/endpoints/following/delete.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
 import ms from 'ms';
-import deleteFollowing from '@/services/following/delete';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { Followings, Users } from '@/models/index';
+import deleteFollowing from '@/services/following/delete.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { Followings, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['following', 'users'],
@@ -19,12 +17,6 @@ export const meta = {
 
 	kind: 'write:following',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -52,8 +44,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const follower = user;
 
 	// Check if the followee is yourself
diff --git a/packages/backend/src/server/api/endpoints/following/invalidate.ts b/packages/backend/src/server/api/endpoints/following/invalidate.ts
index 92e887e00b..24d8256ca6 100644
--- a/packages/backend/src/server/api/endpoints/following/invalidate.ts
+++ b/packages/backend/src/server/api/endpoints/following/invalidate.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import * as ms from 'ms';
-import deleteFollowing from '@/services/following/delete';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { Followings, Users } from '@/models/index';
+import ms from 'ms';
+import deleteFollowing from '@/services/following/delete.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { Followings, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['following', 'users'],
@@ -19,12 +17,6 @@ export const meta = {
 
 	kind: 'write:following',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -52,8 +44,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const followee = user;
 
 	// Check if the follower is yourself
diff --git a/packages/backend/src/server/api/endpoints/following/requests/accept.ts b/packages/backend/src/server/api/endpoints/following/requests/accept.ts
index 7e7c056f55..e5df55375e 100644
--- a/packages/backend/src/server/api/endpoints/following/requests/accept.ts
+++ b/packages/backend/src/server/api/endpoints/following/requests/accept.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import acceptFollowRequest from '@/services/following/requests/accept';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
+import acceptFollowRequest from '@/services/following/requests/accept.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
 
 export const meta = {
 	tags: ['following', 'account'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:following',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch follower
 	const follower = await getUser(ps.userId).catch(e => {
 		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/endpoints/following/requests/cancel.ts b/packages/backend/src/server/api/endpoints/following/requests/cancel.ts
index c9abbf36de..80d37fb075 100644
--- a/packages/backend/src/server/api/endpoints/following/requests/cancel.ts
+++ b/packages/backend/src/server/api/endpoints/following/requests/cancel.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import cancelFollowRequest from '@/services/following/requests/cancel';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { Users } from '@/models/index';
-import { IdentifiableError } from '@/misc/identifiable-error';
+import cancelFollowRequest from '@/services/following/requests/cancel.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { Users } from '@/models/index.js';
+import { IdentifiableError } from '@/misc/identifiable-error.js';
 
 export const meta = {
 	tags: ['following', 'account'],
@@ -14,12 +12,6 @@ export const meta = {
 
 	kind: 'write:following',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -41,8 +33,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch followee
 	const followee = await getUser(ps.userId).catch(e => {
 		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/endpoints/following/requests/list.ts b/packages/backend/src/server/api/endpoints/following/requests/list.ts
index ec0c76502c..3b60b89b3c 100644
--- a/packages/backend/src/server/api/endpoints/following/requests/list.ts
+++ b/packages/backend/src/server/api/endpoints/following/requests/list.ts
@@ -1,5 +1,5 @@
-import define from '../../../define';
-import { FollowRequests } from '@/models/index';
+import define from '../../../define.js';
+import { FollowRequests } from '@/models/index.js';
 
 export const meta = {
 	tags: ['following', 'account'],
@@ -35,8 +35,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const reqs = await FollowRequests.find({
 		followeeId: user.id,
 	});
diff --git a/packages/backend/src/server/api/endpoints/following/requests/reject.ts b/packages/backend/src/server/api/endpoints/following/requests/reject.ts
index a5ce1e7c77..cebe604284 100644
--- a/packages/backend/src/server/api/endpoints/following/requests/reject.ts
+++ b/packages/backend/src/server/api/endpoints/following/requests/reject.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { rejectFollowRequest } from '@/services/following/reject';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
+import { rejectFollowRequest } from '@/services/following/reject.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
 
 export const meta = {
 	tags: ['following', 'account'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:following',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch follower
 	const follower = await getUser(ps.userId).catch(e => {
 		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/endpoints/gallery/featured.ts b/packages/backend/src/server/api/endpoints/gallery/featured.ts
index ff7c16889f..e6acd36911 100644
--- a/packages/backend/src/server/api/endpoints/gallery/featured.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/featured.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { GalleryPosts } from '@/models/index';
+import define from '../../define.js';
+import { GalleryPosts } from '@/models/index.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -17,8 +17,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = GalleryPosts.createQueryBuilder('post')
 		.andWhere('post.createdAt > :date', { date: new Date(Date.now() - (1000 * 60 * 60 * 24 * 3)) })
 		.andWhere('post.likedCount > 0')
diff --git a/packages/backend/src/server/api/endpoints/gallery/popular.ts b/packages/backend/src/server/api/endpoints/gallery/popular.ts
index 2c3368a19d..c4c8982fcc 100644
--- a/packages/backend/src/server/api/endpoints/gallery/popular.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/popular.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { GalleryPosts } from '@/models/index';
+import define from '../../define.js';
+import { GalleryPosts } from '@/models/index.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -17,8 +17,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = GalleryPosts.createQueryBuilder('post')
 		.andWhere('post.likedCount > 0')
 		.orderBy('post.likedCount', 'DESC');
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts.ts b/packages/backend/src/server/api/endpoints/gallery/posts.ts
index 9d2601c7e9..428ba9cc71 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts.ts
@@ -1,27 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { GalleryPosts } from '@/models/index';
+import define from '../../define.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { GalleryPosts } from '@/models/index.js';
 
 export const meta = {
 	tags: ['gallery'],
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -33,12 +16,22 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(GalleryPosts.createQueryBuilder('post'), ps.sinceId, ps.untilId)
 		.innerJoinAndSelect('post.user', 'user');
 
-	const posts = await query.take(ps.limit!).getMany();
+	const posts = await query.take(ps.limit).getMany();
 
 	return await GalleryPosts.packMany(posts, me);
 });
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/create.ts b/packages/backend/src/server/api/endpoints/gallery/posts/create.ts
index e9d5df1ab6..eb6c0f3eb1 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/create.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/create.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
 import ms from 'ms';
-import define from '../../../define';
-import { ID } from '../../../../../misc/cafy-id';
-import { DriveFiles, GalleryPosts } from '@/models/index';
-import { genId } from '../../../../../misc/gen-id';
-import { GalleryPost } from '@/models/entities/gallery-post';
-import { ApiError } from '../../../error';
-import { DriveFile } from '@/models/entities/drive-file';
+import define from '../../../define.js';
+import { DriveFiles, GalleryPosts } from '@/models/index.js';
+import { genId } from '../../../../../misc/gen-id.js';
+import { GalleryPost } from '@/models/entities/gallery-post.js';
+import { ApiError } from '../../../error.js';
+import { DriveFile } from '@/models/entities/drive-file.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -20,25 +18,6 @@ export const meta = {
 		max: 300,
 	},
 
-	params: {
-		title: {
-			validator: $.str.min(1),
-		},
-
-		description: {
-			validator: $.optional.nullable.str,
-		},
-
-		fileIds: {
-			validator: $.arr($.type(ID)).unique().range(1, 32),
-		},
-
-		isSensitive: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -50,8 +29,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		title: { type: 'string', minLength: 1 },
+		description: { type: 'string', nullable: true },
+		fileIds: { type: 'array', uniqueItems: true, minItems: 1, maxItems: 32, items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		isSensitive: { type: 'boolean', default: false },
+	},
+	required: ['title', 'fileIds'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const files = (await Promise.all(ps.fileIds.map(fileId =>
 		DriveFiles.findOne({
 			id: fileId,
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/delete.ts b/packages/backend/src/server/api/endpoints/gallery/posts/delete.ts
index 2a13b9ed58..f8bf785ee6 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/delete.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { GalleryPosts } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { GalleryPosts } from '@/models/index.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:gallery',
 
-	params: {
-		postId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPost: {
 			message: 'No such post.',
@@ -26,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		postId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['postId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const post = await GalleryPosts.findOne({
 		id: ps.postId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/like.ts b/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
index 0fb408fa5f..d154bfc3c6 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/like.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { GalleryPosts, GalleryLikes } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { GalleryPosts, GalleryLikes } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:gallery-likes',
 
-	params: {
-		postId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPost: {
 			message: 'No such post.',
@@ -39,8 +31,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		postId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['postId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const post = await GalleryPosts.findOne(ps.postId);
 	if (post == null) {
 		throw new ApiError(meta.errors.noSuchPost);
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/show.ts b/packages/backend/src/server/api/endpoints/gallery/posts/show.ts
index 4325d2ad37..5b4594070c 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/show.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/show.ts
@@ -1,20 +1,12 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { GalleryPosts } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { GalleryPosts } from '@/models/index.js';
 
 export const meta = {
 	tags: ['gallery'],
 
 	requireCredential: false,
 
-	params: {
-		postId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPost: {
 			message: 'No such post.',
@@ -30,8 +22,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		postId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['postId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const post = await GalleryPosts.findOne({
 		id: ps.postId,
 	});
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/unlike.ts b/packages/backend/src/server/api/endpoints/gallery/posts/unlike.ts
index 9cca09bddc..b00008a864 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/unlike.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/unlike.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { GalleryPosts, GalleryLikes } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { GalleryPosts, GalleryLikes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:gallery-likes',
 
-	params: {
-		postId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPost: {
 			message: 'No such post.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		postId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['postId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const post = await GalleryPosts.findOne(ps.postId);
 	if (post == null) {
 		throw new ApiError(meta.errors.noSuchPost);
diff --git a/packages/backend/src/server/api/endpoints/gallery/posts/update.ts b/packages/backend/src/server/api/endpoints/gallery/posts/update.ts
index c35e1bbf58..123794d08c 100644
--- a/packages/backend/src/server/api/endpoints/gallery/posts/update.ts
+++ b/packages/backend/src/server/api/endpoints/gallery/posts/update.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
 import ms from 'ms';
-import define from '../../../define';
-import { ID } from '../../../../../misc/cafy-id';
-import { DriveFiles, GalleryPosts } from '@/models/index';
-import { GalleryPost } from '@/models/entities/gallery-post';
-import { ApiError } from '../../../error';
-import { DriveFile } from '@/models/entities/drive-file';
+import define from '../../../define.js';
+import { DriveFiles, GalleryPosts } from '@/models/index.js';
+import { GalleryPost } from '@/models/entities/gallery-post.js';
+import { ApiError } from '../../../error.js';
+import { DriveFile } from '@/models/entities/drive-file.js';
 
 export const meta = {
 	tags: ['gallery'],
@@ -19,29 +17,6 @@ export const meta = {
 		max: 300,
 	},
 
-	params: {
-		postId: {
-			validator: $.type(ID),
-		},
-
-		title: {
-			validator: $.str.min(1),
-		},
-
-		description: {
-			validator: $.optional.nullable.str,
-		},
-
-		fileIds: {
-			validator: $.arr($.type(ID)).unique().range(1, 32),
-		},
-
-		isSensitive: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -53,8 +28,22 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		postId: { type: 'string', format: 'misskey:id' },
+		title: { type: 'string', minLength: 1 },
+		description: { type: 'string', nullable: true },
+		fileIds: { type: 'array', uniqueItems: true, minItems: 1, maxItems: 32, items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		isSensitive: { type: 'boolean', default: false },
+	},
+	required: ['postId', 'title', 'fileIds'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const files = (await Promise.all(ps.fileIds.map(fileId =>
 		DriveFiles.findOne({
 			id: fileId,
diff --git a/packages/backend/src/server/api/endpoints/get-online-users-count.ts b/packages/backend/src/server/api/endpoints/get-online-users-count.ts
index 5b13d5a3b8..80a2334cfa 100644
--- a/packages/backend/src/server/api/endpoints/get-online-users-count.ts
+++ b/packages/backend/src/server/api/endpoints/get-online-users-count.ts
@@ -1,19 +1,22 @@
-import { USER_ONLINE_THRESHOLD } from '@/const';
-import { Users } from '@/models/index';
+import { USER_ONLINE_THRESHOLD } from '@/const.js';
+import { Users } from '@/models/index.js';
 import { MoreThan } from 'typeorm';
-import define from '../define';
+import define from '../define.js';
 
 export const meta = {
 	tags: ['meta'],
 
 	requireCredential: false,
+} as const;
 
-	params: {
-	},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const count = await Users.count({
 		lastActiveDate: MoreThan(new Date(Date.now() - USER_ONLINE_THRESHOLD)),
 	});
diff --git a/packages/backend/src/server/api/endpoints/hashtags/list.ts b/packages/backend/src/server/api/endpoints/hashtags/list.ts
index 9fa9b3edc6..50e36386cf 100644
--- a/packages/backend/src/server/api/endpoints/hashtags/list.ts
+++ b/packages/backend/src/server/api/endpoints/hashtags/list.ts
@@ -1,51 +1,11 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Hashtags } from '@/models/index';
+import define from '../../define.js';
+import { Hashtags } from '@/models/index.js';
 
 export const meta = {
 	tags: ['hashtags'],
 
 	requireCredential: false,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		attachedToUserOnly: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		attachedToLocalUserOnly: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		attachedToRemoteUserOnly: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		sort: {
-			validator: $.str.or([
-				'+mentionedUsers',
-				'-mentionedUsers',
-				'+mentionedLocalUsers',
-				'-mentionedLocalUsers',
-				'+mentionedRemoteUsers',
-				'-mentionedRemoteUsers',
-				'+attachedUsers',
-				'-attachedUsers',
-				'+attachedLocalUsers',
-				'-attachedLocalUsers',
-				'+attachedRemoteUsers',
-				'-attachedRemoteUsers',
-			]),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -57,8 +17,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		attachedToUserOnly: { type: 'boolean', default: false },
+		attachedToLocalUserOnly: { type: 'boolean', default: false },
+		attachedToRemoteUserOnly: { type: 'boolean', default: false },
+		sort: { type: 'string', enum: ['+mentionedUsers', '-mentionedUsers', '+mentionedLocalUsers', '-mentionedLocalUsers', '+mentionedRemoteUsers', '-mentionedRemoteUsers', '+attachedUsers', '-attachedUsers', '+attachedLocalUsers', '-attachedLocalUsers', '+attachedRemoteUsers', '-attachedRemoteUsers'] },
+	},
+	required: ['sort'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Hashtags.createQueryBuilder('tag');
 
 	if (ps.attachedToUserOnly) query.andWhere('tag.attachedUsersCount != 0');
@@ -90,7 +62,7 @@ export default define(meta, async (ps, me) => {
 		'tag.attachedRemoteUsersCount',
 	]);
 
-	const tags = await query.take(ps.limit!).getMany();
+	const tags = await query.take(ps.limit).getMany();
 
 	return Hashtags.packMany(tags);
 });
diff --git a/packages/backend/src/server/api/endpoints/hashtags/search.ts b/packages/backend/src/server/api/endpoints/hashtags/search.ts
index 0d646c64f5..c289844775 100644
--- a/packages/backend/src/server/api/endpoints/hashtags/search.ts
+++ b/packages/backend/src/server/api/endpoints/hashtags/search.ts
@@ -1,28 +1,11 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Hashtags } from '@/models/index';
+import define from '../../define.js';
+import { Hashtags } from '@/models/index.js';
 
 export const meta = {
 	tags: ['hashtags'],
 
 	requireCredential: false,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		query: {
-			validator: $.str,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -33,13 +16,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		query: { type: 'string' },
+		offset: { type: 'integer', default: 0 },
+	},
+	required: ['query'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const hashtags = await Hashtags.createQueryBuilder('tag')
 		.where('tag.name like :q', { q: ps.query.toLowerCase() + '%' })
 		.orderBy('tag.count', 'DESC')
 		.groupBy('tag.id')
-		.take(ps.limit!)
+		.take(ps.limit)
 		.skip(ps.offset)
 		.getMany();
 
diff --git a/packages/backend/src/server/api/endpoints/hashtags/show.ts b/packages/backend/src/server/api/endpoints/hashtags/show.ts
index 242cef99d4..6e6afa4f13 100644
--- a/packages/backend/src/server/api/endpoints/hashtags/show.ts
+++ b/packages/backend/src/server/api/endpoints/hashtags/show.ts
@@ -1,20 +1,13 @@
-import $ from 'cafy';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Hashtags } from '@/models/index';
-import { normalizeForSearch } from '@/misc/normalize-for-search';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Hashtags } from '@/models/index.js';
+import { normalizeForSearch } from '@/misc/normalize-for-search.js';
 
 export const meta = {
 	tags: ['hashtags'],
 
 	requireCredential: false,
 
-	params: {
-		tag: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -30,8 +23,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		tag: { type: 'string' },
+	},
+	required: ['tag'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const hashtag = await Hashtags.findOne({ name: normalizeForSearch(ps.tag) });
 	if (hashtag == null) {
 		throw new ApiError(meta.errors.noSuchHashtag);
diff --git a/packages/backend/src/server/api/endpoints/hashtags/trend.ts b/packages/backend/src/server/api/endpoints/hashtags/trend.ts
index be964ad639..9cdbc8941c 100644
--- a/packages/backend/src/server/api/endpoints/hashtags/trend.ts
+++ b/packages/backend/src/server/api/endpoints/hashtags/trend.ts
@@ -1,10 +1,10 @@
 import { Brackets } from 'typeorm';
-import define from '../../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Notes } from '@/models/index';
-import { Note } from '@/models/entities/note';
-import { safeForSql } from '@/misc/safe-for-sql';
-import { normalizeForSearch } from '@/misc/normalize-for-search';
+import define from '../../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Notes } from '@/models/index.js';
+import { Note } from '@/models/entities/note.js';
+import { safeForSql } from '@/misc/safe-for-sql.js';
+import { normalizeForSearch } from '@/misc/normalize-for-search.js';
 
 /*
 トレンドに載るためには「『直近a分間のユニーク投稿数が今からa分前～今からb分前の間のユニーク投稿数のn倍以上』のハッシュタグの上位5位以内に入る」ことが必要
@@ -53,8 +53,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const instance = await fetchMeta(true);
 	const hiddenTags = instance.hiddenTags.map(t => normalizeForSearch(t));
 
diff --git a/packages/backend/src/server/api/endpoints/hashtags/users.ts b/packages/backend/src/server/api/endpoints/hashtags/users.ts
index 2158dc4349..a5df21a7e3 100644
--- a/packages/backend/src/server/api/endpoints/hashtags/users.ts
+++ b/packages/backend/src/server/api/endpoints/hashtags/users.ts
@@ -1,52 +1,12 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Users } from '@/models/index';
-import { normalizeForSearch } from '@/misc/normalize-for-search';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
+import { normalizeForSearch } from '@/misc/normalize-for-search.js';
 
 export const meta = {
 	requireCredential: false,
 
 	tags: ['hashtags', 'users'],
 
-	params: {
-		tag: {
-			validator: $.str,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sort: {
-			validator: $.str.or([
-				'+follower',
-				'-follower',
-				'+createdAt',
-				'-createdAt',
-				'+updatedAt',
-				'-updatedAt',
-			]),
-		},
-
-		state: {
-			validator: $.optional.str.or([
-				'all',
-				'alive',
-			]),
-			default: 'all',
-		},
-
-		origin: {
-			validator: $.optional.str.or([
-				'combined',
-				'local',
-				'remote',
-			]),
-			default: 'local',
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -58,8 +18,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		tag: { type: 'string' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sort: { type: 'string', enum: ['+follower', '-follower', '+createdAt', '-createdAt', '+updatedAt', '-updatedAt'] },
+		state: { type: 'string', enum: ['all', 'alive'], default: "all" },
+		origin: { type: 'string', enum: ['combined', 'local', 'remote'], default: "local" },
+	},
+	required: ['tag', 'sort'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Users.createQueryBuilder('user')
 		.where(':tag = ANY(user.tags)', { tag: normalizeForSearch(ps.tag) });
 
@@ -84,7 +56,7 @@ export default define(meta, async (ps, me) => {
 		case '-updatedAt': query.orderBy('user.updatedAt', 'ASC'); break;
 	}
 
-	const users = await query.take(ps.limit!).getMany();
+	const users = await query.take(ps.limit).getMany();
 
 	return await Users.packMany(users, me, { detail: true });
 });
diff --git a/packages/backend/src/server/api/endpoints/i.ts b/packages/backend/src/server/api/endpoints/i.ts
index d69c118cfc..5b1ad2b098 100644
--- a/packages/backend/src/server/api/endpoints/i.ts
+++ b/packages/backend/src/server/api/endpoints/i.ts
@@ -1,13 +1,11 @@
-import define from '../define';
-import { Users } from '@/models/index';
+import define from '../define.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
 
 	requireCredential: true,
 
-	params: {},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -15,8 +13,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user, token) => {
+export default define(meta, paramDef, async (ps, user, token) => {
 	const isSecure = token == null;
 
 	// ここで渡ってきている user はキャッシュされていて古い可能性もあるので id だけ渡す
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/done.ts b/packages/backend/src/server/api/endpoints/i/2fa/done.ts
index 4853908693..70478430db 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/done.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/done.ts
@@ -1,22 +1,23 @@
-import $ from 'cafy';
 import * as speakeasy from 'speakeasy';
-import define from '../../../define';
-import { UserProfiles } from '@/models/index';
+import define from '../../../define.js';
+import { UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		token: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		token: { type: 'string' },
 	},
+	required: ['token'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const token = ps.token.replace(/\s/g, '');
 
 	const profile = await UserProfiles.findOneOrFail(user.id);
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts b/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts
index 26e9a60886..f33237c8bf 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/key-done.ts
@@ -1,48 +1,40 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import { promisify } from 'util';
+import bcrypt from 'bcryptjs';
+import { promisify } from 'node:util';
 import * as cbor from 'cbor';
-import define from '../../../define';
+import define from '../../../define.js';
 import {
 	UserProfiles,
 	UserSecurityKeys,
 	AttestationChallenges,
 	Users,
-} from '@/models/index';
-import config from '@/config/index';
-import { procedures, hash } from '../../../2fa';
-import { publishMainStream } from '@/services/stream';
+} from '@/models/index.js';
+import config from '@/config/index.js';
+import { procedures, hash } from '../../../2fa.js';
+import { publishMainStream } from '@/services/stream.js';
 
 const cborDecodeFirst = promisify(cbor.decodeFirst) as any;
+const rpIdHashReal = hash(Buffer.from(config.hostname, 'utf-8'));
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		clientDataJSON: {
-			validator: $.str,
-		},
-		attestationObject: {
-			validator: $.str,
-		},
-		password: {
-			validator: $.str,
-		},
-		challengeId: {
-			validator: $.str,
-		},
-		name: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		clientDataJSON: { type: 'string' },
+		attestationObject: { type: 'string' },
+		password: { type: 'string' },
+		challengeId: { type: 'string' },
+		name: { type: 'string' },
 	},
+	required: ['clientDataJSON', 'attestationObject', 'password', 'challengeId', 'name'],
 } as const;
 
-const rpIdHashReal = hash(Buffer.from(config.hostname, 'utf-8'));
-
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/password-less.ts b/packages/backend/src/server/api/endpoints/i/2fa/password-less.ts
index 854848a434..4bfa24f97f 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/password-less.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/password-less.ts
@@ -1,21 +1,22 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { UserProfiles } from '@/models/index';
+import define from '../../../define.js';
+import { UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		value: {
-			validator: $.boolean,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		value: { type: 'boolean' },
 	},
+	required: ['value'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	await UserProfiles.update(user.id, {
 		usePasswordLessLogin: ps.value,
 	});
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts b/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts
index 057e54c69b..0c4c99271e 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/register-key.ts
@@ -1,11 +1,10 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import define from '../../../define';
-import { UserProfiles, AttestationChallenges } from '@/models/index';
-import { promisify } from 'util';
-import * as crypto from 'crypto';
-import { genId } from '@/misc/gen-id';
-import { hash } from '../../../2fa';
+import bcrypt from 'bcryptjs';
+import define from '../../../define.js';
+import { UserProfiles, AttestationChallenges } from '@/models/index.js';
+import { promisify } from 'node:util';
+import * as crypto from 'node:crypto';
+import { genId } from '@/misc/gen-id.js';
+import { hash } from '../../../2fa.js';
 
 const randomBytes = promisify(crypto.randomBytes);
 
@@ -13,16 +12,18 @@ export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		password: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
 	},
+	required: ['password'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/register.ts b/packages/backend/src/server/api/endpoints/i/2fa/register.ts
index c5cfb9dfad..7951e393b8 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/register.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/register.ts
@@ -1,25 +1,26 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
+import bcrypt from 'bcryptjs';
 import * as speakeasy from 'speakeasy';
 import * as QRCode from 'qrcode';
-import config from '@/config/index';
-import define from '../../../define';
-import { UserProfiles } from '@/models/index';
+import config from '@/config/index.js';
+import define from '../../../define.js';
+import { UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		password: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
 	},
+	required: ['password'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/remove-key.ts b/packages/backend/src/server/api/endpoints/i/2fa/remove-key.ts
index 03e1d0434d..2b69b1f8c3 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/remove-key.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/remove-key.ts
@@ -1,26 +1,25 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import define from '../../../define';
-import { UserProfiles, UserSecurityKeys, Users } from '@/models/index';
-import { publishMainStream } from '@/services/stream';
+import bcrypt from 'bcryptjs';
+import define from '../../../define.js';
+import { UserProfiles, UserSecurityKeys, Users } from '@/models/index.js';
+import { publishMainStream } from '@/services/stream.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		password: {
-			validator: $.str,
-		},
-		credentialId: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
+		credentialId: { type: 'string' },
 	},
+	required: ['password', 'credentialId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/2fa/unregister.ts b/packages/backend/src/server/api/endpoints/i/2fa/unregister.ts
index a19ad6810d..c5633f68b1 100644
--- a/packages/backend/src/server/api/endpoints/i/2fa/unregister.ts
+++ b/packages/backend/src/server/api/endpoints/i/2fa/unregister.ts
@@ -1,22 +1,23 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import define from '../../../define';
-import { UserProfiles } from '@/models/index';
+import bcrypt from 'bcryptjs';
+import define from '../../../define.js';
+import { UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		password: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
 	},
+	required: ['password'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/apps.ts b/packages/backend/src/server/api/endpoints/i/apps.ts
index 63999b0981..eca9558847 100644
--- a/packages/backend/src/server/api/endpoints/i/apps.ts
+++ b/packages/backend/src/server/api/endpoints/i/apps.ts
@@ -1,26 +1,22 @@
-import $ from 'cafy';
-import define from '../../define';
-import { AccessTokens } from '@/models/index';
+import define from '../../define.js';
+import { AccessTokens } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		sort: {
-			validator: $.optional.str.or([
-				'+createdAt',
-				'-createdAt',
-				'+lastUsedAt',
-				'-lastUsedAt',
-			]),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		sort: { type: 'string', enum: ['+createdAt', '-createdAt', '+lastUsedAt', '-lastUsedAt'] },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = AccessTokens.createQueryBuilder('token')
 		.where('token.userId = :userId', { userId: user.id });
 
diff --git a/packages/backend/src/server/api/endpoints/i/authorized-apps.ts b/packages/backend/src/server/api/endpoints/i/authorized-apps.ts
index 52122b851b..3301808e75 100644
--- a/packages/backend/src/server/api/endpoints/i/authorized-apps.ts
+++ b/packages/backend/src/server/api/endpoints/i/authorized-apps.ts
@@ -1,38 +1,30 @@
-import $ from 'cafy';
-import define from '../../define';
-import { AccessTokens, Apps } from '@/models/index';
+import define from '../../define.js';
+import { AccessTokens, Apps } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-
-		sort: {
-			validator: $.optional.str.or('desc|asc'),
-			default: 'desc',
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+		sort: { type: 'string', enum: ['desc', 'asc'], default: "desc" },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Get tokens
 	const tokens = await AccessTokens.find({
 		where: {
 			userId: user.id,
 		},
-		take: ps.limit!,
+		take: ps.limit,
 		skip: ps.offset,
 		order: {
 			id: ps.sort == 'asc' ? 1 : -1,
diff --git a/packages/backend/src/server/api/endpoints/i/change-password.ts b/packages/backend/src/server/api/endpoints/i/change-password.ts
index 7b6c137737..16509d2dcf 100644
--- a/packages/backend/src/server/api/endpoints/i/change-password.ts
+++ b/packages/backend/src/server/api/endpoints/i/change-password.ts
@@ -1,26 +1,24 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import define from '../../define';
-import { UserProfiles } from '@/models/index';
+import bcrypt from 'bcryptjs';
+import define from '../../define.js';
+import { UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		currentPassword: {
-			validator: $.str,
-		},
-
-		newPassword: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		currentPassword: { type: 'string' },
+		newPassword: { type: 'string', minLength: 1 },
 	},
+	required: ['currentPassword', 'newPassword'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/delete-account.ts b/packages/backend/src/server/api/endpoints/i/delete-account.ts
index e1eee949fc..8cb6b6a631 100644
--- a/packages/backend/src/server/api/endpoints/i/delete-account.ts
+++ b/packages/backend/src/server/api/endpoints/i/delete-account.ts
@@ -1,25 +1,26 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import define from '../../define';
-import { UserProfiles, Users } from '@/models/index';
-import { doPostSuspend } from '@/services/suspend-user';
-import { publishUserEvent } from '@/services/stream';
-import { createDeleteAccountJob } from '@/queue';
+import bcrypt from 'bcryptjs';
+import define from '../../define.js';
+import { UserProfiles, Users } from '@/models/index.js';
+import { doPostSuspend } from '@/services/suspend-user.js';
+import { publishUserEvent } from '@/services/stream.js';
+import { createDeleteAccountJob } from '@/queue/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		password: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
 	},
+	required: ['password'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 	const userDetailed = await Users.findOneOrFail(user.id);
 	if (userDetailed.isDeleted) {
diff --git a/packages/backend/src/server/api/endpoints/i/export-blocking.ts b/packages/backend/src/server/api/endpoints/i/export-blocking.ts
index 44d8a1cb38..aed4c2e0a3 100644
--- a/packages/backend/src/server/api/endpoints/i/export-blocking.ts
+++ b/packages/backend/src/server/api/endpoints/i/export-blocking.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { createExportBlockingJob } from '@/queue/index';
+import define from '../../define.js';
+import { createExportBlockingJob } from '@/queue/index.js';
 import ms from 'ms';
 
 export const meta = {
@@ -11,7 +11,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createExportBlockingJob(user);
 });
diff --git a/packages/backend/src/server/api/endpoints/i/export-following.ts b/packages/backend/src/server/api/endpoints/i/export-following.ts
index 5d1617d57b..058d77b3c2 100644
--- a/packages/backend/src/server/api/endpoints/i/export-following.ts
+++ b/packages/backend/src/server/api/endpoints/i/export-following.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../../define';
-import { createExportFollowingJob } from '@/queue/index';
+import define from '../../define.js';
+import { createExportFollowingJob } from '@/queue/index.js';
 import ms from 'ms';
 
 export const meta = {
@@ -10,19 +9,18 @@ export const meta = {
 		duration: ms('1hour'),
 		max: 1,
 	},
-	params: {
-		excludeMuting: {
-			validator: $.optional.bool,
-			default: false,
-		},
-		excludeInactive: {
-			validator: $.optional.bool,
-			default: false,
-		},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		excludeMuting: { type: 'boolean', default: false },
+		excludeInactive: { type: 'boolean', default: false },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createExportFollowingJob(user, ps.excludeMuting, ps.excludeInactive);
 });
diff --git a/packages/backend/src/server/api/endpoints/i/export-mute.ts b/packages/backend/src/server/api/endpoints/i/export-mute.ts
index 27ce8f0b29..c0216fac0c 100644
--- a/packages/backend/src/server/api/endpoints/i/export-mute.ts
+++ b/packages/backend/src/server/api/endpoints/i/export-mute.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { createExportMuteJob } from '@/queue/index';
+import define from '../../define.js';
+import { createExportMuteJob } from '@/queue/index.js';
 import ms from 'ms';
 
 export const meta = {
@@ -11,7 +11,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createExportMuteJob(user);
 });
diff --git a/packages/backend/src/server/api/endpoints/i/export-notes.ts b/packages/backend/src/server/api/endpoints/i/export-notes.ts
index 25b1849e80..4b85a45554 100644
--- a/packages/backend/src/server/api/endpoints/i/export-notes.ts
+++ b/packages/backend/src/server/api/endpoints/i/export-notes.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { createExportNotesJob } from '@/queue/index';
+import define from '../../define.js';
+import { createExportNotesJob } from '@/queue/index.js';
 import ms from 'ms';
 
 export const meta = {
@@ -11,7 +11,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createExportNotesJob(user);
 });
diff --git a/packages/backend/src/server/api/endpoints/i/export-user-lists.ts b/packages/backend/src/server/api/endpoints/i/export-user-lists.ts
index d28b699c5a..fa5c1f5e5a 100644
--- a/packages/backend/src/server/api/endpoints/i/export-user-lists.ts
+++ b/packages/backend/src/server/api/endpoints/i/export-user-lists.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { createExportUserListsJob } from '@/queue/index';
+import define from '../../define.js';
+import { createExportUserListsJob } from '@/queue/index.js';
 import ms from 'ms';
 
 export const meta = {
@@ -11,7 +11,13 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	createExportUserListsJob(user);
 });
diff --git a/packages/backend/src/server/api/endpoints/i/favorites.ts b/packages/backend/src/server/api/endpoints/i/favorites.ts
index 92c767876b..3c420e4d0f 100644
--- a/packages/backend/src/server/api/endpoints/i/favorites.ts
+++ b/packages/backend/src/server/api/endpoints/i/favorites.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { NoteFavorites } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { NoteFavorites } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account', 'notes', 'favorites'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:favorites',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,14 +20,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(NoteFavorites.createQueryBuilder('favorite'), ps.sinceId, ps.untilId)
 		.andWhere(`favorite.userId = :meId`, { meId: user.id })
 		.leftJoinAndSelect('favorite.note', 'note');
 
 	const favorites = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await NoteFavorites.packMany(favorites, user);
diff --git a/packages/backend/src/server/api/endpoints/i/gallery/likes.ts b/packages/backend/src/server/api/endpoints/i/gallery/likes.ts
index f1c5763593..a38383f30e 100644
--- a/packages/backend/src/server/api/endpoints/i/gallery/likes.ts
+++ b/packages/backend/src/server/api/endpoints/i/gallery/likes.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { GalleryLikes } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
+import define from '../../../define.js';
+import { GalleryLikes } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account', 'gallery'],
@@ -11,47 +9,46 @@ export const meta = {
 
 	kind: 'read:gallery-likes',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
-		type: 'object',
+		type: 'array',
 		optional: false, nullable: false,
-		properties: {
-			id: {
-				type: 'string',
-				optional: false, nullable: false,
-				format: 'id',
+		items: {
+			type: 'object',
+			optional: false, nullable: false,
+			properties: {
+				id: {
+					type: 'string',
+					optional: false, nullable: false,
+					format: 'id',
+				},
+				post: {
+					type: 'object',
+					optional: false, nullable: false,
+					ref: 'GalleryPost',
+				},
 			},
-			page: {
-				type: 'object',
-				optional: false, nullable: false,
-				ref: 'GalleryPost',
-			},
-		},
+		}
+	},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(GalleryLikes.createQueryBuilder('like'), ps.sinceId, ps.untilId)
 		.andWhere(`like.userId = :meId`, { meId: user.id })
 		.leftJoinAndSelect('like.post', 'post');
 
 	const likes = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await GalleryLikes.packMany(likes, user);
diff --git a/packages/backend/src/server/api/endpoints/i/gallery/posts.ts b/packages/backend/src/server/api/endpoints/i/gallery/posts.ts
index d46d42f633..b4edb5f73d 100644
--- a/packages/backend/src/server/api/endpoints/i/gallery/posts.ts
+++ b/packages/backend/src/server/api/endpoints/i/gallery/posts.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { GalleryPosts } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
+import define from '../../../define.js';
+import { GalleryPosts } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account', 'gallery'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:gallery',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,13 +20,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(GalleryPosts.createQueryBuilder('post'), ps.sinceId, ps.untilId)
 		.andWhere(`post.userId = :meId`, { meId: user.id });
 
 	const posts = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await GalleryPosts.packMany(posts, user);
diff --git a/packages/backend/src/server/api/endpoints/i/get-word-muted-notes-count.ts b/packages/backend/src/server/api/endpoints/i/get-word-muted-notes-count.ts
index 4e1a4d3db9..bc3e0aff47 100644
--- a/packages/backend/src/server/api/endpoints/i/get-word-muted-notes-count.ts
+++ b/packages/backend/src/server/api/endpoints/i/get-word-muted-notes-count.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { MutedNotes } from '@/models/index';
+import define from '../../define.js';
+import { MutedNotes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
@@ -8,9 +8,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -23,8 +20,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	return {
 		count: await MutedNotes.count({
 			userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/i/import-blocking.ts b/packages/backend/src/server/api/endpoints/i/import-blocking.ts
index acc5797420..c70704f9a8 100644
--- a/packages/backend/src/server/api/endpoints/i/import-blocking.ts
+++ b/packages/backend/src/server/api/endpoints/i/import-blocking.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { createImportBlockingJob } from '@/queue/index';
+import define from '../../define.js';
+import { createImportBlockingJob } from '@/queue/index.js';
 import ms from 'ms';
-import { ApiError } from '../../error';
-import { DriveFiles } from '@/models/index';
+import { ApiError } from '../../error.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	secure: true,
@@ -15,12 +13,6 @@ export const meta = {
 		max: 1,
 	},
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -48,8 +40,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) throw new ApiError(meta.errors.noSuchFile);
diff --git a/packages/backend/src/server/api/endpoints/i/import-following.ts b/packages/backend/src/server/api/endpoints/i/import-following.ts
index 35006746fb..7e9175cbf8 100644
--- a/packages/backend/src/server/api/endpoints/i/import-following.ts
+++ b/packages/backend/src/server/api/endpoints/i/import-following.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { createImportFollowingJob } from '@/queue/index';
+import define from '../../define.js';
+import { createImportFollowingJob } from '@/queue/index.js';
 import ms from 'ms';
-import { ApiError } from '../../error';
-import { DriveFiles } from '@/models/index';
+import { ApiError } from '../../error.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	secure: true,
@@ -14,12 +12,6 @@ export const meta = {
 		max: 1,
 	},
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -47,8 +39,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) throw new ApiError(meta.errors.noSuchFile);
diff --git a/packages/backend/src/server/api/endpoints/i/import-muting.ts b/packages/backend/src/server/api/endpoints/i/import-muting.ts
index 7bbb2e008e..abbf07212e 100644
--- a/packages/backend/src/server/api/endpoints/i/import-muting.ts
+++ b/packages/backend/src/server/api/endpoints/i/import-muting.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { createImportMutingJob } from '@/queue/index';
+import define from '../../define.js';
+import { createImportMutingJob } from '@/queue/index.js';
 import ms from 'ms';
-import { ApiError } from '../../error';
-import { DriveFiles } from '@/models/index';
+import { ApiError } from '../../error.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	secure: true,
@@ -15,12 +13,6 @@ export const meta = {
 		max: 1,
 	},
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -48,8 +40,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) throw new ApiError(meta.errors.noSuchFile);
diff --git a/packages/backend/src/server/api/endpoints/i/import-user-lists.ts b/packages/backend/src/server/api/endpoints/i/import-user-lists.ts
index 759d41b6cd..be162817f1 100644
--- a/packages/backend/src/server/api/endpoints/i/import-user-lists.ts
+++ b/packages/backend/src/server/api/endpoints/i/import-user-lists.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { createImportUserListsJob } from '@/queue/index';
+import define from '../../define.js';
+import { createImportUserListsJob } from '@/queue/index.js';
 import ms from 'ms';
-import { ApiError } from '../../error';
-import { DriveFiles } from '@/models/index';
+import { ApiError } from '../../error.js';
+import { DriveFiles } from '@/models/index.js';
 
 export const meta = {
 	secure: true,
@@ -14,12 +12,6 @@ export const meta = {
 		max: 1,
 	},
 
-	params: {
-		fileId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchFile: {
 			message: 'No such file.',
@@ -47,8 +39,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['fileId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const file = await DriveFiles.findOne(ps.fileId);
 
 	if (file == null) throw new ApiError(meta.errors.noSuchFile);
diff --git a/packages/backend/src/server/api/endpoints/i/notifications.ts b/packages/backend/src/server/api/endpoints/i/notifications.ts
index 59efd32bb2..7d9bd44d1d 100644
--- a/packages/backend/src/server/api/endpoints/i/notifications.ts
+++ b/packages/backend/src/server/api/endpoints/i/notifications.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { readNotification } from '../../common/read-notification';
-import define from '../../define';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateMutedInstanceNotificationQuery } from '../../common/generate-muted-instance-query';
-import { Notifications, Followings, Mutings, Users } from '@/models/index';
-import { notificationTypes } from '@/types';
-import read from '@/services/note/read';
+import { readNotification } from '../../common/read-notification.js';
+import define from '../../define.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateMutedInstanceNotificationQuery } from '../../common/generate-muted-instance-query.js';
+import { Notifications, Followings, Mutings, Users } from '@/models/index.js';
+import { notificationTypes } from '@/types.js';
+import read from '@/services/note/read.js';
 import { Brackets } from 'typeorm';
 
 export const meta = {
@@ -16,44 +14,6 @@ export const meta = {
 
 	kind: 'read:notifications',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		following: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		unreadOnly: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		markAsRead: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeTypes: {
-			validator: $.optional.arr($.str.or(notificationTypes as unknown as string[])),
-		},
-
-		excludeTypes: {
-			validator: $.optional.arr($.str.or(notificationTypes as unknown as string[])),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -65,8 +25,27 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		following: { type: 'boolean', default: false },
+		unreadOnly: { type: 'boolean', default: false },
+		markAsRead: { type: 'boolean', default: true },
+		includeTypes: { type: 'array', items: {
+			type: 'string', enum: notificationTypes,
+		} },
+		excludeTypes: { type: 'array', items: {
+			type: 'string', enum: notificationTypes,
+		} },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// includeTypes が空の場合はクエリしない
 	if (ps.includeTypes && ps.includeTypes.length === 0) {
 		return [];
@@ -92,10 +71,16 @@ export default define(meta, async (ps, user) => {
 		.leftJoinAndSelect('notification.notifier', 'notifier')
 		.leftJoinAndSelect('notification.note', 'note')
 		.leftJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	query.andWhere(new Brackets(qb => { qb
 		.where(`notification.notifierId NOT IN (${ mutingQuery.getQuery() })`)
@@ -125,7 +110,7 @@ export default define(meta, async (ps, user) => {
 		query.andWhere(`notification.isRead = false`);
 	}
 
-	const notifications = await query.take(ps.limit!).getMany();
+	const notifications = await query.take(ps.limit).getMany();
 
 	// Mark all as read
 	if (notifications.length > 0 && ps.markAsRead) {
diff --git a/packages/backend/src/server/api/endpoints/i/page-likes.ts b/packages/backend/src/server/api/endpoints/i/page-likes.ts
index 59239c7446..71e326e2f0 100644
--- a/packages/backend/src/server/api/endpoints/i/page-likes.ts
+++ b/packages/backend/src/server/api/endpoints/i/page-likes.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { PageLikes } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { PageLikes } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account', 'pages'],
@@ -11,48 +9,46 @@ export const meta = {
 
 	kind: 'read:page-likes',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
-		type: 'object',
+		type: 'array',
 		optional: false, nullable: false,
-		properties: {
-			id: {
-				type: 'string',
-				optional: false, nullable: false,
-				format: 'id',
+		items: {
+			type: 'object',
+			properties: {
+				id: {
+					type: 'string',
+					optional: false, nullable: false,
+					format: 'id',
+				},
+				page: {
+					type: 'object',
+					optional: false, nullable: false,
+					ref: 'Page',
+				},
 			},
-			page: {
-				type: 'object',
-				optional: false, nullable: false,
-				ref: 'Page',
-			},
-		},
+		}
+	},
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(PageLikes.createQueryBuilder('like'), ps.sinceId, ps.untilId)
 		.andWhere(`like.userId = :meId`, { meId: user.id })
 		.leftJoinAndSelect('like.page', 'page');
 
 	const likes = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
-	return await PageLikes.packMany(likes, user);
+	return PageLikes.packMany(likes, user);
 });
diff --git a/packages/backend/src/server/api/endpoints/i/pages.ts b/packages/backend/src/server/api/endpoints/i/pages.ts
index bef775d063..f28aed3fd4 100644
--- a/packages/backend/src/server/api/endpoints/i/pages.ts
+++ b/packages/backend/src/server/api/endpoints/i/pages.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Pages } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Pages } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account', 'pages'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:pages',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,13 +20,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Pages.createQueryBuilder('page'), ps.sinceId, ps.untilId)
 		.andWhere(`page.userId = :meId`, { meId: user.id });
 
 	const pages = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Pages.packMany(pages);
diff --git a/packages/backend/src/server/api/endpoints/i/pin.ts b/packages/backend/src/server/api/endpoints/i/pin.ts
index a940d1b99b..67b7026be1 100644
--- a/packages/backend/src/server/api/endpoints/i/pin.ts
+++ b/packages/backend/src/server/api/endpoints/i/pin.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { addPinned } from '@/services/i/pin';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Users } from '@/models/index';
+import { addPinned } from '@/services/i/pin.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account', 'notes'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -45,8 +37,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	await addPinned(user, ps.noteId).catch(e => {
 		if (e.id === '70c4e51f-5bea-449c-a030-53bee3cce202') throw new ApiError(meta.errors.noSuchNote);
 		if (e.id === '15a018eb-58e5-4da1-93be-330fcc5e4e1a') throw new ApiError(meta.errors.pinLimitExceeded);
diff --git a/packages/backend/src/server/api/endpoints/i/read-all-messaging-messages.ts b/packages/backend/src/server/api/endpoints/i/read-all-messaging-messages.ts
index 4e4fb3840f..2e291a34a0 100644
--- a/packages/backend/src/server/api/endpoints/i/read-all-messaging-messages.ts
+++ b/packages/backend/src/server/api/endpoints/i/read-all-messaging-messages.ts
@@ -1,6 +1,6 @@
-import { publishMainStream } from '@/services/stream';
-import define from '../../define';
-import { MessagingMessages, UserGroupJoinings } from '@/models/index';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../../define.js';
+import { MessagingMessages, UserGroupJoinings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account', 'messaging'],
@@ -8,13 +8,16 @@ export const meta = {
 	requireCredential: true,
 
 	kind: 'write:account',
+} as const;
 
-	params: {
-	},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Update documents
 	await MessagingMessages.update({
 		recipientId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/i/read-all-unread-notes.ts b/packages/backend/src/server/api/endpoints/i/read-all-unread-notes.ts
index 99f17ddfc9..49f3deb331 100644
--- a/packages/backend/src/server/api/endpoints/i/read-all-unread-notes.ts
+++ b/packages/backend/src/server/api/endpoints/i/read-all-unread-notes.ts
@@ -1,6 +1,6 @@
-import { publishMainStream } from '@/services/stream';
-import define from '../../define';
-import { NoteUnreads } from '@/models/index';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../../define.js';
+import { NoteUnreads } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
@@ -8,13 +8,16 @@ export const meta = {
 	requireCredential: true,
 
 	kind: 'write:account',
+} as const;
 
-	params: {
-	},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Remove documents
 	await NoteUnreads.delete({
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/i/read-announcement.ts b/packages/backend/src/server/api/endpoints/i/read-announcement.ts
index e9bb66264b..647fa77fa4 100644
--- a/packages/backend/src/server/api/endpoints/i/read-announcement.ts
+++ b/packages/backend/src/server/api/endpoints/i/read-announcement.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { genId } from '@/misc/gen-id';
-import { AnnouncementReads, Announcements, Users } from '@/models/index';
-import { publishMainStream } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { genId } from '@/misc/gen-id.js';
+import { AnnouncementReads, Announcements, Users } from '@/models/index.js';
+import { publishMainStream } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['account'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		announcementId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchAnnouncement: {
 			message: 'No such announcement.',
@@ -28,8 +20,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		announcementId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['announcementId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Check if announcement exists
 	const announcement = await Announcements.findOne(ps.announcementId);
 
diff --git a/packages/backend/src/server/api/endpoints/i/regenerate-token.ts b/packages/backend/src/server/api/endpoints/i/regenerate-token.ts
index a20719363b..771c98b212 100644
--- a/packages/backend/src/server/api/endpoints/i/regenerate-token.ts
+++ b/packages/backend/src/server/api/endpoints/i/regenerate-token.ts
@@ -1,24 +1,25 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import { publishMainStream, publishUserEvent } from '@/services/stream';
-import generateUserToken from '../../common/generate-native-user-token';
-import define from '../../define';
-import { Users, UserProfiles } from '@/models/index';
+import bcrypt from 'bcryptjs';
+import { publishMainStream, publishUserEvent } from '@/services/stream.js';
+import generateUserToken from '../../common/generate-native-user-token.js';
+import define from '../../define.js';
+import { Users, UserProfiles } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		password: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
 	},
+	required: ['password'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/registry/get-all.ts b/packages/backend/src/server/api/endpoints/i/registry/get-all.ts
index 2941b441e2..d0b16dbc48 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/get-all.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/get-all.ts
@@ -1,22 +1,24 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.where('item.domain IS NULL')
 		.andWhere('item.userId = :userId', { userId: user.id })
diff --git a/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts b/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts
index 51371353c9..cc5d5a8c6f 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/get-detail.ts
@@ -1,24 +1,12 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
 
-	params: {
-		key: {
-			validator: $.str,
-		},
-
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
-	},
-
 	errors: {
 		noSuchKey: {
 			message: 'No such key.',
@@ -28,8 +16,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		key: { type: 'string' },
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
+	},
+	required: ['key'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.where('item.domain IS NULL')
 		.andWhere('item.userId = :userId', { userId: user.id })
diff --git a/packages/backend/src/server/api/endpoints/i/registry/get.ts b/packages/backend/src/server/api/endpoints/i/registry/get.ts
index ac617defb0..a79319744c 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/get.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/get.ts
@@ -1,24 +1,12 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
 
-	params: {
-		key: {
-			validator: $.str,
-		},
-
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
-	},
-
 	errors: {
 		noSuchKey: {
 			message: 'No such key.',
@@ -28,8 +16,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		key: { type: 'string' },
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
+	},
+	required: ['key'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.where('item.domain IS NULL')
 		.andWhere('item.userId = :userId', { userId: user.id })
diff --git a/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts b/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts
index 0445922188..ac209c06a6 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/keys-with-type.ts
@@ -1,22 +1,24 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.where('item.domain IS NULL')
 		.andWhere('item.userId = :userId', { userId: user.id })
diff --git a/packages/backend/src/server/api/endpoints/i/registry/keys.ts b/packages/backend/src/server/api/endpoints/i/registry/keys.ts
index a3c9d0e5ee..5ea1a9d344 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/keys.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/keys.ts
@@ -1,22 +1,24 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.select('item.key')
 		.where('item.domain IS NULL')
diff --git a/packages/backend/src/server/api/endpoints/i/registry/remove.ts b/packages/backend/src/server/api/endpoints/i/registry/remove.ts
index 08185f224b..92473654c6 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/remove.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/remove.ts
@@ -1,24 +1,12 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
 
-	params: {
-		key: {
-			validator: $.str,
-		},
-
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
-	},
-
 	errors: {
 		noSuchKey: {
 			message: 'No such key.',
@@ -28,8 +16,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		key: { type: 'string' },
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
+	},
+	required: ['key'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.where('item.domain IS NULL')
 		.andWhere('item.userId = :userId', { userId: user.id })
diff --git a/packages/backend/src/server/api/endpoints/i/registry/scopes.ts b/packages/backend/src/server/api/endpoints/i/registry/scopes.ts
index 9de68ac6e8..de4b313e25 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/scopes.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/scopes.ts
@@ -1,17 +1,20 @@
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-	},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.select('item.scope')
 		.where('item.domain IS NULL')
diff --git a/packages/backend/src/server/api/endpoints/i/registry/set.ts b/packages/backend/src/server/api/endpoints/i/registry/set.ts
index 27884046b4..d380b428a3 100644
--- a/packages/backend/src/server/api/endpoints/i/registry/set.ts
+++ b/packages/backend/src/server/api/endpoints/i/registry/set.ts
@@ -1,32 +1,28 @@
-import $ from 'cafy';
-import { publishMainStream } from '@/services/stream';
-import define from '../../../define';
-import { RegistryItems } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../../../define.js';
+import { RegistryItems } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		key: {
-			validator: $.str.min(1),
-		},
-
-		value: {
-			validator: $.nullable.any,
-		},
-
-		scope: {
-			validator: $.optional.arr($.str.match(/^[a-zA-Z0-9_]+$/)),
-			default: [],
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		key: { type: 'string', minLength: 1 },
+		value: {},
+		scope: { type: 'array', default: [], items: {
+			type: 'string', pattern: /^[a-zA-Z0-9_]+$/.toString().slice(1, -1),
+		} },
 	},
+	required: ['key', 'value'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = RegistryItems.createQueryBuilder('item')
 		.where('item.domain IS NULL')
 		.andWhere('item.userId = :userId', { userId: user.id })
diff --git a/packages/backend/src/server/api/endpoints/i/revoke-token.ts b/packages/backend/src/server/api/endpoints/i/revoke-token.ts
index 51721c5b58..b957fd0796 100644
--- a/packages/backend/src/server/api/endpoints/i/revoke-token.ts
+++ b/packages/backend/src/server/api/endpoints/i/revoke-token.ts
@@ -1,23 +1,23 @@
-import $ from 'cafy';
-import define from '../../define';
-import { AccessTokens } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
-import { publishUserEvent } from '@/services/stream';
+import define from '../../define.js';
+import { AccessTokens } from '@/models/index.js';
+import { publishUserEvent } from '@/services/stream.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		tokenId: {
-			validator: $.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		tokenId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['tokenId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const token = await AccessTokens.findOne(ps.tokenId);
 
 	if (token) {
diff --git a/packages/backend/src/server/api/endpoints/i/signin-history.ts b/packages/backend/src/server/api/endpoints/i/signin-history.ts
index 796e2ec309..ca37411662 100644
--- a/packages/backend/src/server/api/endpoints/i/signin-history.ts
+++ b/packages/backend/src/server/api/endpoints/i/signin-history.ts
@@ -1,36 +1,29 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Signins } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Signins } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	requireCredential: true,
 
 	secure: true,
+} as const;
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Signins.createQueryBuilder('signin'), ps.sinceId, ps.untilId)
 		.andWhere(`signin.userId = :meId`, { meId: user.id });
 
-	const history = await query.take(ps.limit!).getMany();
+	const history = await query.take(ps.limit).getMany();
 
 	return await Promise.all(history.map(record => Signins.pack(record)));
 });
diff --git a/packages/backend/src/server/api/endpoints/i/unpin.ts b/packages/backend/src/server/api/endpoints/i/unpin.ts
index 9c82b74960..9912689da5 100644
--- a/packages/backend/src/server/api/endpoints/i/unpin.ts
+++ b/packages/backend/src/server/api/endpoints/i/unpin.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { removePinned } from '@/services/i/pin';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Users } from '@/models/index';
+import { removePinned } from '@/services/i/pin.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account', 'notes'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -33,8 +25,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	await removePinned(user, ps.noteId).catch(e => {
 		if (e.id === 'b302d4cf-c050-400a-bbb3-be208681f40c') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/i/update-email.ts b/packages/backend/src/server/api/endpoints/i/update-email.ts
index b4479aa50d..389ff1b81d 100644
--- a/packages/backend/src/server/api/endpoints/i/update-email.ts
+++ b/packages/backend/src/server/api/endpoints/i/update-email.ts
@@ -1,14 +1,13 @@
-import $ from 'cafy';
-import { publishMainStream } from '@/services/stream';
-import define from '../../define';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../../define.js';
 import rndstr from 'rndstr';
-import config from '@/config/index';
+import config from '@/config/index.js';
 import ms from 'ms';
-import * as bcrypt from 'bcryptjs';
-import { Users, UserProfiles } from '@/models/index';
-import { sendEmail } from '@/services/send-email';
-import { ApiError } from '../../error';
-import { validateEmailForAccount } from '@/services/validate-email-for-account';
+import bcrypt from 'bcryptjs';
+import { Users, UserProfiles } from '@/models/index.js';
+import { sendEmail } from '@/services/send-email.js';
+import { ApiError } from '../../error.js';
+import { validateEmailForAccount } from '@/services/validate-email-for-account.js';
 
 export const meta = {
 	requireCredential: true,
@@ -20,16 +19,6 @@ export const meta = {
 		max: 3,
 	},
 
-	params: {
-		password: {
-			validator: $.str,
-		},
-
-		email: {
-			validator: $.optional.nullable.str,
-		},
-	},
-
 	errors: {
 		incorrectPassword: {
 			message: 'Incorrect password.',
@@ -45,8 +34,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		password: { type: 'string' },
+		email: { type: 'string', nullable: true },
+	},
+	required: ['password'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const profile = await UserProfiles.findOneOrFail(user.id);
 
 	// Compare password
diff --git a/packages/backend/src/server/api/endpoints/i/update.ts b/packages/backend/src/server/api/endpoints/i/update.ts
index aec7bbd2e1..85d0a62548 100644
--- a/packages/backend/src/server/api/endpoints/i/update.ts
+++ b/packages/backend/src/server/api/endpoints/i/update.ts
@@ -1,21 +1,19 @@
-const RE2 = require('re2');
-import $ from 'cafy';
+import RE2 from 're2';
 import * as mfm from 'mfm-js';
-import { ID } from '@/misc/cafy-id';
-import { publishMainStream, publishUserEvent } from '@/services/stream';
-import acceptAllFollowRequests from '@/services/following/requests/accept-all';
-import { publishToFollowers } from '@/services/i/update';
-import define from '../../define';
-import { extractCustomEmojisFromMfm } from '@/misc/extract-custom-emojis-from-mfm';
-import { extractHashtags } from '@/misc/extract-hashtags';
-import * as langmap from 'langmap';
-import { updateUsertags } from '@/services/update-hashtag';
-import { ApiError } from '../../error';
-import { Users, DriveFiles, UserProfiles, Pages } from '@/models/index';
-import { User } from '@/models/entities/user';
-import { UserProfile } from '@/models/entities/user-profile';
-import { notificationTypes } from '@/types';
-import { normalizeForSearch } from '@/misc/normalize-for-search';
+import { publishMainStream, publishUserEvent } from '@/services/stream.js';
+import acceptAllFollowRequests from '@/services/following/requests/accept-all.js';
+import { publishToFollowers } from '@/services/i/update.js';
+import define from '../../define.js';
+import { extractCustomEmojisFromMfm } from '@/misc/extract-custom-emojis-from-mfm.js';
+import { extractHashtags } from '@/misc/extract-hashtags.js';
+import { updateUsertags } from '@/services/update-hashtag.js';
+import { ApiError } from '../../error.js';
+import { Users, DriveFiles, UserProfiles, Pages } from '@/models/index.js';
+import { User } from '@/models/entities/user.js';
+import { UserProfile } from '@/models/entities/user-profile.js';
+import { notificationTypes } from '@/types.js';
+import { normalizeForSearch } from '@/misc/normalize-for-search.js';
+import { langmap } from '@/misc/langmap.js';
 
 export const meta = {
 	tags: ['account'],
@@ -24,116 +22,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		name: {
-			validator: $.optional.nullable.use(Users.validateName),
-		},
-
-		description: {
-			validator: $.optional.nullable.use(Users.validateDescription),
-		},
-
-		lang: {
-			validator: $.optional.nullable.str.or(Object.keys(langmap)),
-		},
-
-		location: {
-			validator: $.optional.nullable.use(Users.validateLocation),
-		},
-
-		birthday: {
-			validator: $.optional.nullable.use(Users.validateBirthday),
-		},
-
-		avatarId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		bannerId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		fields: {
-			validator: $.optional.arr($.object()).range(1, 4),
-		},
-
-		isLocked: {
-			validator: $.optional.bool,
-		},
-
-		isExplorable: {
-			validator: $.optional.bool,
-		},
-
-		hideOnlineStatus: {
-			validator: $.optional.bool,
-		},
-
-		publicReactions: {
-			validator: $.optional.bool,
-		},
-
-		ffVisibility: {
-			validator: $.optional.str,
-		},
-
-		carefulBot: {
-			validator: $.optional.bool,
-		},
-
-		autoAcceptFollowed: {
-			validator: $.optional.bool,
-		},
-
-		noCrawle: {
-			validator: $.optional.bool,
-		},
-
-		isBot: {
-			validator: $.optional.bool,
-		},
-
-		isCat: {
-			validator: $.optional.bool,
-		},
-
-		showTimelineReplies: {
-			validator: $.optional.bool,
-		},
-
-		injectFeaturedNote: {
-			validator: $.optional.bool,
-		},
-
-		receiveAnnouncementEmail: {
-			validator: $.optional.bool,
-		},
-
-		alwaysMarkNsfw: {
-			validator: $.optional.bool,
-		},
-
-		pinnedPageId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		mutedWords: {
-			validator: $.optional.arr($.either($.arr($.str.min(1)).min(1), $.str)),
-		},
-
-		mutedInstances: {
-			validator: $.optional.arr($.str),
-		},
-
-		mutingNotificationTypes: {
-			validator: $.optional.arr($.str.or(notificationTypes as unknown as string[])),
-		},
-
-		emailNotificationTypes: {
-			validator: $.optional.arr($.str),
-		},
-	},
-
 	errors: {
 		noSuchAvatar: {
 			message: 'No such avatar file.',
@@ -179,8 +67,60 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { ...Users.nameSchema, nullable: true },
+		description: { ...Users.descriptionSchema, nullable: true },
+		location: { ...Users.locationSchema, nullable: true },
+		birthday: { ...Users.birthdaySchema, nullable: true },
+		lang: { type: 'string', enum: [null, ...Object.keys(langmap)], nullable: true },
+		avatarId: { type: 'string', format: 'misskey:id', nullable: true },
+		bannerId: { type: 'string', format: 'misskey:id', nullable: true },
+		fields: { type: 'array',
+			minItems: 0,
+			maxItems: 16,
+			items: {
+				type: 'object',
+				properties: {
+					name: { type: 'string' },
+					value: { type: 'string' },
+				},
+				required: ['name', 'value'],
+			},
+		},
+		isLocked: { type: 'boolean' },
+		isExplorable: { type: 'boolean' },
+		hideOnlineStatus: { type: 'boolean' },
+		publicReactions: { type: 'boolean' },
+		carefulBot: { type: 'boolean' },
+		autoAcceptFollowed: { type: 'boolean' },
+		noCrawle: { type: 'boolean' },
+		isBot: { type: 'boolean' },
+		isCat: { type: 'boolean' },
+		showTimelineReplies: { type: 'boolean' },
+		injectFeaturedNote: { type: 'boolean' },
+		receiveAnnouncementEmail: { type: 'boolean' },
+		alwaysMarkNsfw: { type: 'boolean' },
+		ffVisibility: { type: 'string', enum: ['public', 'followers', 'private'] },
+		pinnedPageId: { type: 'array', items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		mutedWords: { type: 'array' },
+		mutedInstances: { type: 'array', items: {
+			type: 'string',
+		} },
+		mutingNotificationTypes: { type: 'array', items: {
+			type: 'string', enum: notificationTypes,
+		} },
+		emailNotificationTypes: { type: 'array', items: {
+			type: 'string',
+		} },
+	},
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, _user, token) => {
+export default define(meta, paramDef, async (ps, _user, token) => {
 	const user = await Users.findOneOrFail(_user.id);
 	const isSecure = token == null;
 
@@ -235,12 +175,6 @@ export default define(meta, async (ps, _user, token) => {
 
 		if (avatar == null || avatar.userId !== user.id) throw new ApiError(meta.errors.noSuchAvatar);
 		if (!avatar.type.startsWith('image/')) throw new ApiError(meta.errors.avatarNotAnImage);
-
-		updates.avatarUrl = DriveFiles.getPublicUrl(avatar, true);
-
-		if (avatar.blurhash) {
-			updates.avatarBlurhash = avatar.blurhash;
-		}
 	}
 
 	if (ps.bannerId) {
@@ -248,12 +182,6 @@ export default define(meta, async (ps, _user, token) => {
 
 		if (banner == null || banner.userId !== user.id) throw new ApiError(meta.errors.noSuchBanner);
 		if (!banner.type.startsWith('image/')) throw new ApiError(meta.errors.bannerNotAnImage);
-
-		updates.bannerUrl = DriveFiles.getPublicUrl(banner, false);
-
-		if (banner.blurhash) {
-			updates.bannerBlurhash = banner.blurhash;
-		}
 	}
 
 	if (ps.pinnedPageId) {
diff --git a/packages/backend/src/server/api/endpoints/i/user-group-invites.ts b/packages/backend/src/server/api/endpoints/i/user-group-invites.ts
index 76a3131e6d..1d7e4a16b3 100644
--- a/packages/backend/src/server/api/endpoints/i/user-group-invites.ts
+++ b/packages/backend/src/server/api/endpoints/i/user-group-invites.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { UserGroupInvitations } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { UserGroupInvitations } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['account', 'groups'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:user-groups',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -48,14 +31,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(UserGroupInvitations.createQueryBuilder('invitation'), ps.sinceId, ps.untilId)
 		.andWhere(`invitation.userId = :meId`, { meId: user.id })
 		.leftJoinAndSelect('invitation.userGroup', 'user_group');
 
 	const invitations = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await UserGroupInvitations.packMany(invitations);
diff --git a/packages/backend/src/server/api/endpoints/messaging/history.ts b/packages/backend/src/server/api/endpoints/messaging/history.ts
index 5ac49cf96b..14de4e1028 100644
--- a/packages/backend/src/server/api/endpoints/messaging/history.ts
+++ b/packages/backend/src/server/api/endpoints/messaging/history.ts
@@ -1,7 +1,6 @@
-import $ from 'cafy';
-import define from '../../define';
-import { MessagingMessage } from '@/models/entities/messaging-message';
-import { MessagingMessages, Mutings, UserGroupJoinings } from '@/models/index';
+import define from '../../define.js';
+import { MessagingMessage } from '@/models/entities/messaging-message.js';
+import { MessagingMessages, Mutings, UserGroupJoinings } from '@/models/index.js';
 import { Brackets } from 'typeorm';
 
 export const meta = {
@@ -11,18 +10,6 @@ export const meta = {
 
 	kind: 'read:messaging',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		group: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -34,8 +21,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		group: { type: 'boolean', default: false },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const mute = await Mutings.find({
 		muterId: user.id,
 	});
@@ -50,7 +46,7 @@ export default define(meta, async (ps, user) => {
 
 	const history: MessagingMessage[] = [];
 
-	for (let i = 0; i < ps.limit!; i++) {
+	for (let i = 0; i < ps.limit; i++) {
 		const found = ps.group
 			? history.map(m => m.groupId!)
 			: history.map(m => (m.userId === user.id) ? m.recipientId! : m.userId!);
diff --git a/packages/backend/src/server/api/endpoints/messaging/messages.ts b/packages/backend/src/server/api/endpoints/messaging/messages.ts
index 7dbddd80e2..49ace21600 100644
--- a/packages/backend/src/server/api/endpoints/messaging/messages.ts
+++ b/packages/backend/src/server/api/endpoints/messaging/messages.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { MessagingMessages, UserGroups, UserGroupJoinings, Users } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { MessagingMessages, UserGroups, UserGroupJoinings, Users } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 import { Brackets } from 'typeorm';
-import { readUserMessagingMessage, readGroupMessagingMessage, deliverReadActivity } from '../../common/read-messaging-message';
+import { readUserMessagingMessage, readGroupMessagingMessage, deliverReadActivity } from '../../common/read-messaging-message.js';
 
 export const meta = {
 	tags: ['messaging'],
@@ -15,34 +13,6 @@ export const meta = {
 
 	kind: 'read:messaging',
 
-	params: {
-		userId: {
-			validator: $.optional.type(ID),
-		},
-
-		groupId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		markAsRead: {
-			validator: $.optional.bool,
-			default: true,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -74,8 +44,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		groupId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		markAsRead: { type: 'boolean', default: true },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	if (ps.userId != null) {
 		// Fetch recipient (user)
 		const recipient = await getUser(ps.userId).catch(e => {
@@ -97,7 +80,7 @@ export default define(meta, async (ps, user) => {
 			.setParameter('meId', user.id)
 			.setParameter('recipientId', recipient.id);
 
-		const messages = await query.take(ps.limit!).getMany();
+		const messages = await query.take(ps.limit).getMany();
 
 		// Mark all as read
 		if (ps.markAsRead) {
@@ -133,7 +116,7 @@ export default define(meta, async (ps, user) => {
 		const query = makePaginationQuery(MessagingMessages.createQueryBuilder('message'), ps.sinceId, ps.untilId)
 			.andWhere(`message.groupId = :groupId`, { groupId: recipientGroup.id });
 
-		const messages = await query.take(ps.limit!).getMany();
+		const messages = await query.take(ps.limit).getMany();
 
 		// Mark all as read
 		if (ps.markAsRead) {
diff --git a/packages/backend/src/server/api/endpoints/messaging/messages/create.ts b/packages/backend/src/server/api/endpoints/messaging/messages/create.ts
index 5ec16f5e5a..a9b926c4fb 100644
--- a/packages/backend/src/server/api/endpoints/messaging/messages/create.ts
+++ b/packages/backend/src/server/api/endpoints/messaging/messages/create.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { MessagingMessages, DriveFiles, UserGroups, UserGroupJoinings, Blockings } from '@/models/index';
-import { User } from '@/models/entities/user';
-import { UserGroup } from '@/models/entities/user-group';
-import { createMessage } from '@/services/messages/create';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { MessagingMessages, DriveFiles, UserGroups, UserGroupJoinings, Blockings } from '@/models/index.js';
+import { User } from '@/models/entities/user.js';
+import { UserGroup } from '@/models/entities/user-group.js';
+import { createMessage } from '@/services/messages/create.js';
 
 export const meta = {
 	tags: ['messaging'],
@@ -15,24 +13,6 @@ export const meta = {
 
 	kind: 'write:messaging',
 
-	params: {
-		userId: {
-			validator: $.optional.type(ID),
-		},
-
-		groupId: {
-			validator: $.optional.type(ID),
-		},
-
-		text: {
-			validator: $.optional.str.pipe(MessagingMessages.validateText),
-		},
-
-		fileId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -84,8 +64,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		groupId: { type: 'string', format: 'misskey:id' },
+		text: { type: 'string', nullable: true, maxLength: 3000 },
+		fileId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let recipientUser: User | undefined;
 	let recipientGroup: UserGroup | undefined;
 
diff --git a/packages/backend/src/server/api/endpoints/messaging/messages/delete.ts b/packages/backend/src/server/api/endpoints/messaging/messages/delete.ts
index 2975419cef..a0945af510 100644
--- a/packages/backend/src/server/api/endpoints/messaging/messages/delete.ts
+++ b/packages/backend/src/server/api/endpoints/messaging/messages/delete.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
+import define from '../../../define.js';
 import ms from 'ms';
-import { ApiError } from '../../../error';
-import { MessagingMessages } from '@/models/index';
-import { deleteMessage } from '@/services/messages/delete';
+import { ApiError } from '../../../error.js';
+import { MessagingMessages } from '@/models/index.js';
+import { deleteMessage } from '@/services/messages/delete.js';
 
 export const meta = {
 	tags: ['messaging'],
@@ -19,12 +17,6 @@ export const meta = {
 		minInterval: ms('1sec'),
 	},
 
-	params: {
-		messageId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchMessage: {
 			message: 'No such message.',
@@ -34,8 +26,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		messageId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['messageId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const message = await MessagingMessages.findOne({
 		id: ps.messageId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/messaging/messages/read.ts b/packages/backend/src/server/api/endpoints/messaging/messages/read.ts
index 42c3f49f6f..8d38e509ac 100644
--- a/packages/backend/src/server/api/endpoints/messaging/messages/read.ts
+++ b/packages/backend/src/server/api/endpoints/messaging/messages/read.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { MessagingMessages } from '@/models/index';
-import { readUserMessagingMessage, readGroupMessagingMessage } from '../../../common/read-messaging-message';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { MessagingMessages } from '@/models/index.js';
+import { readUserMessagingMessage, readGroupMessagingMessage } from '../../../common/read-messaging-message.js';
 
 export const meta = {
 	tags: ['messaging'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:messaging',
 
-	params: {
-		messageId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchMessage: {
 			message: 'No such message.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		messageId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['messageId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const message = await MessagingMessages.findOne(ps.messageId);
 
 	if (message == null) {
diff --git a/packages/backend/src/server/api/endpoints/meta.ts b/packages/backend/src/server/api/endpoints/meta.ts
index 16ea99af69..1aff1f63fb 100644
--- a/packages/backend/src/server/api/endpoints/meta.ts
+++ b/packages/backend/src/server/api/endpoints/meta.ts
@@ -1,23 +1,16 @@
-import $ from 'cafy';
-import config from '@/config/index';
-import define from '../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Ads, Emojis, Users } from '@/models/index';
-import { DB_MAX_NOTE_TEXT_LENGTH } from '@/misc/hard-limits';
+import config from '@/config/index.js';
+import define from '../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Ads, Emojis, Users } from '@/models/index.js';
+import { DB_MAX_NOTE_TEXT_LENGTH } from '@/misc/hard-limits.js';
 import { MoreThan } from 'typeorm';
+import { MAX_NOTE_TEXT_LENGTH } from '@/const.js';
 
 export const meta = {
 	tags: ['meta'],
 
 	requireCredential: false,
 
-	params: {
-		detail: {
-			validator: $.optional.bool,
-			default: true,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -71,10 +64,13 @@ export const meta = {
 				optional: false, nullable: false,
 				default: 'https://github.com/misskey-dev/misskey/issues/new',
 			},
-			secure: {
-				type: 'boolean',
-				optional: false, nullable: false,
-				default: false,
+			defaultDarkTheme: {
+				type: 'string',
+				optional: false, nullable: true,
+			},
+			defaultLightTheme: {
+				type: 'string',
+				optional: false, nullable: true,
 			},
 			disableRegistration: {
 				type: 'boolean',
@@ -100,10 +96,6 @@ export const meta = {
 				type: 'boolean',
 				optional: false, nullable: false,
 			},
-			proxyRemoteFiles: {
-				type: 'boolean',
-				optional: false, nullable: false,
-			},
 			emailRequiredForSignup: {
 				type: 'boolean',
 				optional: false, nullable: false,
@@ -149,7 +141,6 @@ export const meta = {
 			maxNoteTextLength: {
 				type: 'number',
 				optional: false, nullable: false,
-				default: 500,
 			},
 			emojis: {
 				type: 'array',
@@ -448,8 +439,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		detail: { type: 'boolean', default: true },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const instance = await fetchMeta(true);
 
 	const emojis = await Emojis.find({
@@ -485,9 +484,6 @@ export default define(meta, async (ps, me) => {
 		tosUrl: instance.ToSUrl,
 		repositoryUrl: instance.repositoryUrl,
 		feedbackUrl: instance.feedbackUrl,
-
-		secure: config.https != null,
-
 		disableRegistration: instance.disableRegistration,
 		disableLocalTimeline: instance.disableLocalTimeline,
 		disableGlobalTimeline: instance.disableGlobalTimeline,
@@ -506,8 +502,10 @@ export default define(meta, async (ps, me) => {
 		iconUrl: instance.iconUrl,
 		backgroundImageUrl: instance.backgroundImageUrl,
 		logoImageUrl: instance.logoImageUrl,
-		maxNoteTextLength: Math.min(instance.maxNoteTextLength, DB_MAX_NOTE_TEXT_LENGTH),
+		maxNoteTextLength: MAX_NOTE_TEXT_LENGTH, // 後方互換性のため
 		emojis: await Emojis.packMany(emojis),
+		defaultLightTheme: instance.defaultLightTheme,
+		defaultDarkTheme: instance.defaultDarkTheme,
 		ads: ads.map(ad => ({
 			id: ad.id,
 			url: ad.url,
@@ -529,7 +527,6 @@ export default define(meta, async (ps, me) => {
 			pinnedPages: instance.pinnedPages,
 			pinnedClipId: instance.pinnedClipId,
 			cacheRemoteFiles: instance.cacheRemoteFiles,
-			proxyRemoteFiles: instance.proxyRemoteFiles,
 			requireSetup: (await Users.count({
 				host: null,
 			})) === 0,
diff --git a/packages/backend/src/server/api/endpoints/miauth/gen-token.ts b/packages/backend/src/server/api/endpoints/miauth/gen-token.ts
index 158c8877e9..73ecdaeb03 100644
--- a/packages/backend/src/server/api/endpoints/miauth/gen-token.ts
+++ b/packages/backend/src/server/api/endpoints/miauth/gen-token.ts
@@ -1,8 +1,7 @@
-import $ from 'cafy';
-import define from '../../define';
-import { AccessTokens } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { secureRndstr } from '@/misc/secure-rndstr';
+import define from '../../define.js';
+import { AccessTokens } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { secureRndstr } from '@/misc/secure-rndstr.js';
 
 export const meta = {
 	tags: ['auth'],
@@ -11,28 +10,6 @@ export const meta = {
 
 	secure: true,
 
-	params: {
-		session: {
-			validator: $.nullable.str,
-		},
-
-		name: {
-			validator: $.nullable.optional.str,
-		},
-
-		description: {
-			validator: $.nullable.optional.str,
-		},
-
-		iconUrl: {
-			validator: $.nullable.optional.str,
-		},
-
-		permission: {
-			validator: $.arr($.str).unique(),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -45,8 +22,22 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		session: { type: 'string', nullable: true },
+		name: { type: 'string', nullable: true },
+		description: { type: 'string', nullable: true },
+		iconUrl: { type: 'string', nullable: true },
+		permission: { type: 'array', uniqueItems: true, items: {
+			type: 'string',
+		} },
+	},
+	required: ['session', 'permission'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Generate access token
 	const accessToken = secureRndstr(32, true);
 
diff --git a/packages/backend/src/server/api/endpoints/mute/create.ts b/packages/backend/src/server/api/endpoints/mute/create.ts
index 6ba5a453c3..dacee40d01 100644
--- a/packages/backend/src/server/api/endpoints/mute/create.ts
+++ b/packages/backend/src/server/api/endpoints/mute/create.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { genId } from '@/misc/gen-id';
-import { Mutings, NoteWatchings } from '@/models/index';
-import { Muting } from '@/models/entities/muting';
-import { publishUserEvent } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { genId } from '@/misc/gen-id.js';
+import { Mutings, NoteWatchings } from '@/models/index.js';
+import { Muting } from '@/models/entities/muting.js';
+import { publishUserEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['account'],
@@ -15,12 +13,6 @@ export const meta = {
 
 	kind: 'write:mutes',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -42,8 +34,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		expiresAt: { type: 'integer', nullable: true },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const muter = user;
 
 	// 自分自身
@@ -67,10 +68,15 @@ export default define(meta, async (ps, user) => {
 		throw new ApiError(meta.errors.alreadyMuting);
 	}
 
+	if (ps.expiresAt && ps.expiresAt <= Date.now()) {
+		return;
+	}
+
 	// Create mute
 	await Mutings.insert({
 		id: genId(),
 		createdAt: new Date(),
+		expiresAt: ps.expiresAt ? new Date(ps.expiresAt) : null,
 		muterId: muter.id,
 		muteeId: mutee.id,
 	} as Muting);
diff --git a/packages/backend/src/server/api/endpoints/mute/delete.ts b/packages/backend/src/server/api/endpoints/mute/delete.ts
index 21948dc3d1..a8cf2a6667 100644
--- a/packages/backend/src/server/api/endpoints/mute/delete.ts
+++ b/packages/backend/src/server/api/endpoints/mute/delete.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { Mutings } from '@/models/index';
-import { publishUserEvent } from '@/services/stream';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { Mutings } from '@/models/index.js';
+import { publishUserEvent } from '@/services/stream.js';
 
 export const meta = {
 	tags: ['account'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:mutes',
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -40,8 +32,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const muter = user;
 
 	// Check if the mutee is yourself
diff --git a/packages/backend/src/server/api/endpoints/mute/list.ts b/packages/backend/src/server/api/endpoints/mute/list.ts
index 4c6a81b63c..31283cf4c1 100644
--- a/packages/backend/src/server/api/endpoints/mute/list.ts
+++ b/packages/backend/src/server/api/endpoints/mute/list.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Mutings } from '@/models/index';
+import define from '../../define.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { Mutings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
@@ -11,21 +9,6 @@ export const meta = {
 
 	kind: 'read:mutes',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 30,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -37,13 +20,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 30 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Mutings.createQueryBuilder('muting'), ps.sinceId, ps.untilId)
 		.andWhere(`muting.muterId = :meId`, { meId: me.id });
 
 	const mutings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Mutings.packMany(mutings, me);
diff --git a/packages/backend/src/server/api/endpoints/my/apps.ts b/packages/backend/src/server/api/endpoints/my/apps.ts
index 42bd5c5f75..85b75c15df 100644
--- a/packages/backend/src/server/api/endpoints/my/apps.ts
+++ b/packages/backend/src/server/api/endpoints/my/apps.ts
@@ -1,83 +1,40 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Apps } from '@/models/index';
+import define from '../../define.js';
+import { Apps } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account', 'app'],
 
 	requireCredential: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
 		items: {
 			type: 'object',
 			optional: false, nullable: false,
-			properties: {
-				id: {
-					type: 'string',
-					optional: false, nullable: false,
-				},
-				name: {
-					type: 'string',
-					optional: false, nullable: false,
-				},
-				callbackUrl: {
-					type: 'string',
-					optional: false, nullable: false,
-				},
-				permission: {
-					type: 'array',
-					optional: false, nullable: false,
-					items: {
-						type: 'string',
-						optional: false, nullable: false,
-					},
-				},
-				secret: {
-					type: 'string',
-					optional: true, nullable: false,
-				},
-				isAuthorized: {
-					type: 'object',
-					optional: true, nullable: false,
-					properties: {
-						appId: {
-							type: 'string',
-							optional: false, nullable: false,
-						},
-						userId: {
-							type: 'string',
-							optional: false, nullable: false,
-						},
-					},
-				},
-			},
+			ref: 'App',
 		},
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = {
 		userId: user.id,
 	};
 
 	const apps = await Apps.find({
 		where: query,
-		take: ps.limit!,
+		take: ps.limit,
 		skip: ps.offset,
 	});
 
diff --git a/packages/backend/src/server/api/endpoints/notes.ts b/packages/backend/src/server/api/endpoints/notes.ts
index 9edc6cb11c..96657f8d3f 100644
--- a/packages/backend/src/server/api/endpoints/notes.ts
+++ b/packages/backend/src/server/api/endpoints/notes.ts
@@ -1,47 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../define';
-import { makePaginationQuery } from '../common/make-pagination-query';
-import { Notes } from '@/models/index';
+import define from '../define.js';
+import { makePaginationQuery } from '../common/make-pagination-query.js';
+import { Notes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
 
-	params: {
-		local: {
-			validator: $.optional.bool,
-		},
-
-		reply: {
-			validator: $.optional.bool,
-		},
-
-		renote: {
-			validator: $.optional.bool,
-		},
-
-		withFiles: {
-			validator: $.optional.bool,
-		},
-
-		poll: {
-			validator: $.optional.bool,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -53,16 +16,37 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		local: { type: 'boolean' },
+		reply: { type: 'boolean' },
+		renote: { type: 'boolean' },
+		withFiles: { type: 'boolean' },
+		poll: { type: 'boolean' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.andWhere(`note.visibility = 'public'`)
 		.andWhere(`note.localOnly = FALSE`)
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	if (ps.local) {
 		query.andWhere('note.userHost IS NULL');
@@ -89,7 +73,7 @@ export default define(meta, async (ps) => {
 	//	query.isBot = bot;
 	//}
 
-	const notes = await query.take(ps.limit!).getMany();
+	const notes = await query.take(ps.limit).getMany();
 
 	return await Notes.packMany(notes);
 });
diff --git a/packages/backend/src/server/api/endpoints/notes/children.ts b/packages/backend/src/server/api/endpoints/notes/children.ts
index 088ef65e96..86dde30d64 100644
--- a/packages/backend/src/server/api/endpoints/notes/children.ts
+++ b/packages/backend/src/server/api/endpoints/notes/children.ts
@@ -1,38 +1,17 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
+import define from '../../define.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
 import { Brackets } from 'typeorm';
-import { Notes } from '@/models/index';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
-import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query';
+import { Notes } from '@/models/index.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
+import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -44,8 +23,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.andWhere(new Brackets(qb => { qb
 			.where(`note.replyId = :noteId`, { noteId: ps.noteId })
@@ -59,17 +49,23 @@ export default define(meta, async (ps, user) => {
 			}));
 		}))
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateVisibilityQuery(query, user);
 	if (user) generateMutedUserQuery(query, user);
 	if (user) generateBlockedUserQuery(query, user);
 	if (user) generateMutedInstanceQuery(query, user);
 
-	const notes = await query.take(ps.limit!).getMany();
+	const notes = await query.take(ps.limit).getMany();
 
 	return await Notes.packMany(notes, user);
 });
diff --git a/packages/backend/src/server/api/endpoints/notes/clips.ts b/packages/backend/src/server/api/endpoints/notes/clips.ts
index b89c6db4a8..9a863b7148 100644
--- a/packages/backend/src/server/api/endpoints/notes/clips.ts
+++ b/packages/backend/src/server/api/endpoints/notes/clips.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ClipNotes, Clips } from '@/models/index';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
+import define from '../../define.js';
+import { ClipNotes, Clips } from '@/models/index.js';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
 import { In } from 'typeorm';
 
 export const meta = {
@@ -11,12 +9,6 @@ export const meta = {
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -36,8 +28,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/conversation.ts b/packages/backend/src/server/api/endpoints/notes/conversation.ts
index 4bd89c32e7..2552c0f99d 100644
--- a/packages/backend/src/server/api/endpoints/notes/conversation.ts
+++ b/packages/backend/src/server/api/endpoints/notes/conversation.ts
@@ -1,32 +1,14 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getNote } from '../../common/getters';
-import { Note } from '@/models/entities/note';
-import { Notes } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getNote } from '../../common/getters.js';
+import { Note } from '@/models/entities/note.js';
+import { Notes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -46,8 +28,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
@@ -65,7 +57,7 @@ export default define(meta, async (ps, user) => {
 			conversation.push(p);
 		}
 
-		if (conversation.length == ps.limit!) {
+		if (conversation.length == ps.limit) {
 			return;
 		}
 
diff --git a/packages/backend/src/server/api/endpoints/notes/create.ts b/packages/backend/src/server/api/endpoints/notes/create.ts
index 4efa76b248..e4a9b28891 100644
--- a/packages/backend/src/server/api/endpoints/notes/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/create.ts
@@ -1,26 +1,14 @@
-import $ from 'cafy';
 import ms from 'ms';
-import { length } from 'stringz';
-import create from '@/services/note/create';
-import define from '../../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { ApiError } from '../../error';
-import { ID } from '@/misc/cafy-id';
-import { User } from '@/models/entities/user';
-import { Users, DriveFiles, Notes, Channels, Blockings } from '@/models/index';
-import { DriveFile } from '@/models/entities/drive-file';
-import { Note } from '@/models/entities/note';
-import { DB_MAX_NOTE_TEXT_LENGTH } from '@/misc/hard-limits';
-import { noteVisibilities } from '../../../../types';
-import { Channel } from '@/models/entities/channel';
-
-let maxNoteTextLength = 500;
-
-setInterval(() => {
-	fetchMeta().then(m => {
-		maxNoteTextLength = m.maxNoteTextLength;
-	});
-}, 3000);
+import create from '@/services/note/create.js';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { User } from '@/models/entities/user.js';
+import { Users, DriveFiles, Notes, Channels, Blockings } from '@/models/index.js';
+import { DriveFile } from '@/models/entities/drive-file.js';
+import { Note } from '@/models/entities/note.js';
+import { noteVisibilities } from '../../../../types.js';
+import { Channel } from '@/models/entities/channel.js';
+import { MAX_NOTE_TEXT_LENGTH } from '@/const.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -34,84 +22,6 @@ export const meta = {
 
 	kind: 'write:notes',
 
-	params: {
-		visibility: {
-			validator: $.optional.str.or(noteVisibilities as unknown as string[]),
-			default: 'public',
-		},
-
-		visibleUserIds: {
-			validator: $.optional.arr($.type(ID)).unique().min(0),
-		},
-
-		text: {
-			validator: $.optional.nullable.str.pipe(text =>
-				text.trim() != ''
-					&& length(text.trim()) <= maxNoteTextLength
-					&& Array.from(text.trim()).length <= DB_MAX_NOTE_TEXT_LENGTH,	// DB limit
-			),
-			default: null,
-		},
-
-		cw: {
-			validator: $.optional.nullable.str.pipe(Notes.validateCw),
-		},
-
-		localOnly: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		noExtractMentions: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		noExtractHashtags: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		noExtractEmojis: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		fileIds: {
-			validator: $.optional.arr($.type(ID)).unique().range(1, 16),
-		},
-
-		mediaIds: {
-			validator: $.optional.arr($.type(ID)).unique().range(1, 16),
-			deprecated: true,
-		},
-
-		replyId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		renoteId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		channelId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		poll: {
-			validator: $.optional.nullable.obj({
-				choices: $.arr($.str)
-					.unique()
-					.range(2, 10)
-					.each(c => c.length > 0 && c.length < 50),
-				multiple: $.optional.bool,
-				expiresAt: $.optional.nullable.num.int(),
-				expiredAfter: $.optional.nullable.num.int().min(1),
-			}).strict(),
-			ref: 'poll',
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -175,8 +85,49 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		visibility: { type: 'string', enum: ['public', 'home', 'followers', 'specified'], default: "public" },
+		visibleUserIds: { type: 'array', uniqueItems: true, items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		text: { type: 'string', nullable: true, maxLength: MAX_NOTE_TEXT_LENGTH, default: null },
+		cw: { type: 'string', nullable: true, maxLength: 100 },
+		localOnly: { type: 'boolean', default: false },
+		noExtractMentions: { type: 'boolean', default: false },
+		noExtractHashtags: { type: 'boolean', default: false },
+		noExtractEmojis: { type: 'boolean', default: false },
+		fileIds: { type: 'array', uniqueItems: true, minItems: 1, maxItems: 16, items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		mediaIds: { type: 'array', uniqueItems: true, minItems: 1, maxItems: 16, items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		replyId: { type: 'string', format: 'misskey:id', nullable: true },
+		renoteId: { type: 'string', format: 'misskey:id', nullable: true },
+		channelId: { type: 'string', format: 'misskey:id', nullable: true },
+		poll: {
+			type: 'object', nullable: true,
+			properties: {
+				choices: {
+					type: 'array', uniqueItems: true, minItems: 2, maxItems: 10, 
+					items: {
+						type: 'string', minLength: 1, maxLength: 50,
+					},
+				},
+				multiple: { type: 'boolean', default: false },
+				expiresAt: { type: 'integer', nullable: true },
+				expiredAfter: { type: 'integer', nullable: true, minimum: 1 },
+			},
+			required: ['choices'],
+		},
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let visibleUsers: User[] = [];
 	if (ps.visibleUserIds) {
 		visibleUsers = (await Promise.all(ps.visibleUserIds.map(id => Users.findOne(id))))
diff --git a/packages/backend/src/server/api/endpoints/notes/delete.ts b/packages/backend/src/server/api/endpoints/notes/delete.ts
index 9e080d9e99..22ff2275ca 100644
--- a/packages/backend/src/server/api/endpoints/notes/delete.ts
+++ b/packages/backend/src/server/api/endpoints/notes/delete.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import deleteNote from '@/services/note/delete';
-import define from '../../define';
+import deleteNote from '@/services/note/delete.js';
+import define from '../../define.js';
 import ms from 'ms';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
-import { Users } from '@/models/index';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -20,12 +18,6 @@ export const meta = {
 		minInterval: ms('1sec'),
 	},
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -41,8 +33,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/favorites/create.ts b/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
index 78da6a3b00..bcc2c44c02 100644
--- a/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/favorites/create.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getNote } from '../../../common/getters';
-import { NoteFavorites } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getNote } from '../../../common/getters.js';
+import { NoteFavorites } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['notes', 'favorites'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:favorites',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -34,8 +26,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Get favoritee
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
diff --git a/packages/backend/src/server/api/endpoints/notes/favorites/delete.ts b/packages/backend/src/server/api/endpoints/notes/favorites/delete.ts
index 3f3d50f0d5..d41fab22d3 100644
--- a/packages/backend/src/server/api/endpoints/notes/favorites/delete.ts
+++ b/packages/backend/src/server/api/endpoints/notes/favorites/delete.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getNote } from '../../../common/getters';
-import { NoteFavorites } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getNote } from '../../../common/getters.js';
+import { NoteFavorites } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes', 'favorites'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:favorites',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -33,8 +25,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Get favoritee
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
diff --git a/packages/backend/src/server/api/endpoints/notes/featured.ts b/packages/backend/src/server/api/endpoints/notes/featured.ts
index 5a47fb9e08..6308d23696 100644
--- a/packages/backend/src/server/api/endpoints/notes/featured.ts
+++ b/packages/backend/src/server/api/endpoints/notes/featured.ts
@@ -1,26 +1,13 @@
-import $ from 'cafy';
-import define from '../../define';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { Notes } from '@/models/index';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import define from '../../define.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { Notes } from '@/models/index.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -32,8 +19,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const max = 30;
 	const day = 1000 * 60 * 60 * 24 * 3; // 3日前まで
 
@@ -44,10 +40,16 @@ export default define(meta, async (ps, user) => {
 		.andWhere(`note.createdAt > :date`, { date: new Date(Date.now() - day) })
 		.andWhere(`note.visibility = 'public'`)
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	if (user) generateMutedUserQuery(query, user);
 	if (user) generateBlockedUserQuery(query, user);
diff --git a/packages/backend/src/server/api/endpoints/notes/global-timeline.ts b/packages/backend/src/server/api/endpoints/notes/global-timeline.ts
index cdd110994e..26aaa0919c 100644
--- a/packages/backend/src/server/api/endpoints/notes/global-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/global-timeline.ts
@@ -1,47 +1,18 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { ApiError } from '../../error';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Notes } from '@/models/index';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query';
-import { activeUsersChart } from '@/services/chart/index';
-import { generateRepliesQuery } from '../../common/generate-replies-query';
-import { generateMutedNoteQuery } from '../../common/generate-muted-note-query';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import define from '../../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { ApiError } from '../../error.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { Notes } from '@/models/index.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query.js';
+import { activeUsersChart } from '@/services/chart/index.js';
+import { generateRepliesQuery } from '../../common/generate-replies-query.js';
+import { generateMutedNoteQuery } from '../../common/generate-muted-note-query.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
-	params: {
-		withFiles: {
-			validator: $.optional.bool,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -61,8 +32,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		withFiles: { type: 'boolean' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const m = await fetchMeta();
 	if (m.disableGlobalTimeline) {
 		if (user == null || (!user.isAdmin && !user.isModerator)) {
@@ -76,10 +60,16 @@ export default define(meta, async (ps, user) => {
 		.andWhere('note.visibility = \'public\'')
 		.andWhere('note.channelId IS NULL')
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateRepliesQuery(query, user);
 	if (user) generateMutedUserQuery(query, user);
@@ -92,7 +82,7 @@ export default define(meta, async (ps, user) => {
 	}
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	process.nextTick(() => {
 		if (user) {
diff --git a/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts b/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
index b438491026..9bcb64b656 100644
--- a/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/hybrid-timeline.ts
@@ -1,67 +1,23 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { ApiError } from '../../error';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Followings, Notes } from '@/models/index';
+import define from '../../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { ApiError } from '../../error.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { Followings, Notes } from '@/models/index.js';
 import { Brackets } from 'typeorm';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query';
-import { activeUsersChart } from '@/services/chart/index';
-import { generateRepliesQuery } from '../../common/generate-replies-query';
-import { generateMutedNoteQuery } from '../../common/generate-muted-note-query';
-import { generateChannelQuery } from '../../common/generate-channel-query';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query.js';
+import { activeUsersChart } from '@/services/chart/index.js';
+import { generateRepliesQuery } from '../../common/generate-replies-query.js';
+import { generateMutedNoteQuery } from '../../common/generate-muted-note-query.js';
+import { generateChannelQuery } from '../../common/generate-channel-query.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-
-		includeMyRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeRenotedMyNotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeLocalRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		withFiles: {
-			validator: $.optional.bool,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -81,8 +37,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+		includeMyRenotes: { type: 'boolean', default: true },
+		includeRenotedMyNotes: { type: 'boolean', default: true },
+		includeLocalRenotes: { type: 'boolean', default: true },
+		withFiles: { type: 'boolean' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const m = await fetchMeta();
 	if (m.disableLocalTimeline && !user.isAdmin && !user.isModerator) {
 		throw new ApiError(meta.errors.stlDisabled);
@@ -100,10 +72,16 @@ export default define(meta, async (ps, user) => {
 				.orWhere('(note.visibility = \'public\') AND (note.userHost IS NULL)');
 		}))
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
 		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner')
 		.setParameters(followingQuery.getParameters());
 
 	generateChannelQuery(query, user);
@@ -149,7 +127,7 @@ export default define(meta, async (ps, user) => {
 	}
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	process.nextTick(() => {
 		if (user) {
diff --git a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
index ce0bcbeb7b..12fc88b1fd 100644
--- a/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/local-timeline.ts
@@ -1,58 +1,20 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { ApiError } from '../../error';
-import { Notes } from '@/models/index';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { activeUsersChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { ApiError } from '../../error.js';
+import { Notes } from '@/models/index.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { activeUsersChart } from '@/services/chart/index.js';
 import { Brackets } from 'typeorm';
-import { generateRepliesQuery } from '../../common/generate-replies-query';
-import { generateMutedNoteQuery } from '../../common/generate-muted-note-query';
-import { generateChannelQuery } from '../../common/generate-channel-query';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import { generateRepliesQuery } from '../../common/generate-replies-query.js';
+import { generateMutedNoteQuery } from '../../common/generate-muted-note-query.js';
+import { generateChannelQuery } from '../../common/generate-channel-query.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
-	params: {
-		withFiles: {
-			validator: $.optional.bool,
-		},
-
-		fileType: {
-			validator: $.optional.arr($.str),
-		},
-
-		excludeNsfw: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -72,8 +34,25 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		withFiles: { type: 'boolean' },
+		fileType: { type: 'array', items: {
+			type: 'string',
+		} },
+		excludeNsfw: { type: 'boolean', default: false },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const m = await fetchMeta();
 	if (m.disableLocalTimeline) {
 		if (user == null || (!user.isAdmin && !user.isModerator)) {
@@ -86,10 +65,16 @@ export default define(meta, async (ps, user) => {
 			ps.sinceId, ps.untilId, ps.sinceDate, ps.untilDate)
 		.andWhere('(note.visibility = \'public\') AND (note.userHost IS NULL)')
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateChannelQuery(query, user);
 	generateRepliesQuery(query, user);
@@ -118,7 +103,7 @@ export default define(meta, async (ps, user) => {
 	}
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	process.nextTick(() => {
 		if (user) {
diff --git a/packages/backend/src/server/api/endpoints/notes/mentions.ts b/packages/backend/src/server/api/endpoints/notes/mentions.ts
index 81b3844365..eafbba322d 100644
--- a/packages/backend/src/server/api/endpoints/notes/mentions.ts
+++ b/packages/backend/src/server/api/endpoints/notes/mentions.ts
@@ -1,44 +1,18 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import read from '@/services/note/read';
-import { Notes, Followings } from '@/models/index';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import read from '@/services/note/read.js';
+import { Notes, Followings } from '@/models/index.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 import { Brackets } from 'typeorm';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
-import { generateMutedNoteThreadQuery } from '../../common/generate-muted-note-thread-query';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
+import { generateMutedNoteThreadQuery } from '../../common/generate-muted-note-thread-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: true,
 
-	params: {
-		following: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		visibility: {
-			validator: $.optional.str,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -50,8 +24,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		following: { type: 'boolean', default: false },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		visibility: { type: 'string' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const followingQuery = Followings.createQueryBuilder('following')
 		.select('following.followeeId')
 		.where('following.followerId = :followerId', { followerId: user.id });
@@ -62,10 +48,16 @@ export default define(meta, async (ps, user) => {
 			.orWhere(`'{"${user.id}"}' <@ note.visibleUserIds`);
 		}))
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateVisibilityQuery(query, user);
 	generateMutedUserQuery(query, user);
@@ -81,7 +73,7 @@ export default define(meta, async (ps, user) => {
 		query.setParameters(followingQuery.getParameters());
 	}
 
-	const mentions = await query.take(ps.limit!).getMany();
+	const mentions = await query.take(ps.limit).getMany();
 
 	read(user.id, mentions);
 
diff --git a/packages/backend/src/server/api/endpoints/notes/polls/recommendation.ts b/packages/backend/src/server/api/endpoints/notes/polls/recommendation.ts
index 79b558e65e..bdd1aeecd4 100644
--- a/packages/backend/src/server/api/endpoints/notes/polls/recommendation.ts
+++ b/packages/backend/src/server/api/endpoints/notes/polls/recommendation.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { Polls, Mutings, Notes, PollVotes } from '@/models/index';
+import define from '../../../define.js';
+import { Polls, Mutings, Notes, PollVotes } from '@/models/index.js';
 import { Brackets, In } from 'typeorm';
 
 export const meta = {
@@ -8,18 +7,6 @@ export const meta = {
 
 	requireCredential: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -31,8 +18,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = Polls.createQueryBuilder('poll')
 		.where('poll.userHost IS NULL')
 		.andWhere(`poll.userId != :meId`, { meId: user.id })
@@ -64,7 +60,7 @@ export default define(meta, async (ps, user) => {
 	query.setParameters(mutingQuery.getParameters());
 	//#endregion
 
-	const polls = await query.take(ps.limit!).skip(ps.offset).getMany();
+	const polls = await query.take(ps.limit).skip(ps.offset).getMany();
 
 	if (polls.length === 0) return [];
 
diff --git a/packages/backend/src/server/api/endpoints/notes/polls/vote.ts b/packages/backend/src/server/api/endpoints/notes/polls/vote.ts
index 77387cacb2..ef52d03664 100644
--- a/packages/backend/src/server/api/endpoints/notes/polls/vote.ts
+++ b/packages/backend/src/server/api/endpoints/notes/polls/vote.ts
@@ -1,18 +1,16 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { publishNoteStream } from '@/services/stream';
-import { createNotification } from '@/services/create-notification';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getNote } from '../../../common/getters';
-import { deliver } from '@/queue/index';
-import { renderActivity } from '@/remote/activitypub/renderer/index';
-import renderVote from '@/remote/activitypub/renderer/vote';
-import { deliverQuestionUpdate } from '@/services/note/polls/update';
-import { PollVotes, NoteWatchings, Users, Polls, Blockings } from '@/models/index';
+import { publishNoteStream } from '@/services/stream.js';
+import { createNotification } from '@/services/create-notification.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getNote } from '../../../common/getters.js';
+import { deliver } from '@/queue/index.js';
+import { renderActivity } from '@/remote/activitypub/renderer/index.js';
+import renderVote from '@/remote/activitypub/renderer/vote.js';
+import { deliverQuestionUpdate } from '@/services/note/polls/update.js';
+import { PollVotes, NoteWatchings, Users, Polls, Blockings } from '@/models/index.js';
 import { Not } from 'typeorm';
-import { IRemoteUser } from '@/models/entities/user';
-import { genId } from '@/misc/gen-id';
+import { IRemoteUser } from '@/models/entities/user.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -21,16 +19,6 @@ export const meta = {
 
 	kind: 'write:votes',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		choice: {
-			validator: $.num,
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -70,8 +58,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		choice: { type: 'integer' },
+	},
+	required: ['noteId', 'choice'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const createdAt = new Date();
 
 	// Get votee
diff --git a/packages/backend/src/server/api/endpoints/notes/reactions.ts b/packages/backend/src/server/api/endpoints/notes/reactions.ts
index 5205a78171..43e5d1ef6f 100644
--- a/packages/backend/src/server/api/endpoints/notes/reactions.ts
+++ b/packages/backend/src/server/api/endpoints/notes/reactions.ts
@@ -1,45 +1,15 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
-import { NoteReactions } from '@/models/index';
+import define from '../../define.js';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
+import { NoteReactions } from '@/models/index.js';
 import { DeepPartial } from 'typeorm';
-import { NoteReaction } from '@/models/entities/note-reaction';
+import { NoteReaction } from '@/models/entities/note-reaction.js';
 
 export const meta = {
 	tags: ['notes', 'reactions'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		type: {
-			validator: $.optional.nullable.str,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num,
-			default: 0,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -59,8 +29,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		type: { type: 'string', nullable: true },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
@@ -80,11 +63,12 @@ export default define(meta, async (ps, user) => {
 
 	const reactions = await NoteReactions.find({
 		where: query,
-		take: ps.limit!,
+		take: ps.limit,
 		skip: ps.offset,
 		order: {
 			id: -1,
 		},
+		relations: ['user', 'user.avatar', 'user.banner', 'note'],
 	});
 
 	return await Promise.all(reactions.map(reaction => NoteReactions.pack(reaction, user)));
diff --git a/packages/backend/src/server/api/endpoints/notes/reactions/create.ts b/packages/backend/src/server/api/endpoints/notes/reactions/create.ts
index 1b42781ceb..07e52a9266 100644
--- a/packages/backend/src/server/api/endpoints/notes/reactions/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/reactions/create.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import createReaction from '@/services/note/reaction/create';
-import define from '../../../define';
-import { getNote } from '../../../common/getters';
-import { ApiError } from '../../../error';
+import createReaction from '@/services/note/reaction/create.js';
+import define from '../../../define.js';
+import { getNote } from '../../../common/getters.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['reactions', 'notes'],
@@ -12,16 +10,6 @@ export const meta = {
 
 	kind: 'write:reactions',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		reaction: {
-			validator: $.str,
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -43,8 +31,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		reaction: { type: 'string' },
+	},
+	required: ['noteId', 'reaction'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/reactions/delete.ts b/packages/backend/src/server/api/endpoints/notes/reactions/delete.ts
index 1d686b5971..639ecae264 100644
--- a/packages/backend/src/server/api/endpoints/notes/reactions/delete.ts
+++ b/packages/backend/src/server/api/endpoints/notes/reactions/delete.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
+import define from '../../../define.js';
 import ms from 'ms';
-import deleteReaction from '@/services/note/reaction/delete';
-import { getNote } from '../../../common/getters';
-import { ApiError } from '../../../error';
+import deleteReaction from '@/services/note/reaction/delete.js';
+import { getNote } from '../../../common/getters.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['reactions', 'notes'],
@@ -19,12 +17,6 @@ export const meta = {
 		minInterval: ms('3sec'),
 	},
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -40,8 +32,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/renotes.ts b/packages/backend/src/server/api/endpoints/notes/renotes.ts
index f71d23146a..87c855a5e8 100644
--- a/packages/backend/src/server/api/endpoints/notes/renotes.ts
+++ b/packages/backend/src/server/api/endpoints/notes/renotes.ts
@@ -1,38 +1,17 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Notes } from '@/models/index';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import define from '../../define.js';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { Notes } from '@/models/index.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -52,8 +31,19 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
@@ -62,16 +52,22 @@ export default define(meta, async (ps, user) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.andWhere(`note.renoteId = :renoteId`, { renoteId: note.id })
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateVisibilityQuery(query, user);
 	if (user) generateMutedUserQuery(query, user);
 	if (user) generateBlockedUserQuery(query, user);
 
-	const renotes = await query.take(ps.limit!).getMany();
+	const renotes = await query.take(ps.limit).getMany();
 
 	return await Notes.packMany(renotes, user);
 });
diff --git a/packages/backend/src/server/api/endpoints/notes/replies.ts b/packages/backend/src/server/api/endpoints/notes/replies.ts
index 62c56534e1..3053eabe33 100644
--- a/packages/backend/src/server/api/endpoints/notes/replies.ts
+++ b/packages/backend/src/server/api/endpoints/notes/replies.ts
@@ -1,36 +1,15 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Notes } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import define from '../../define.js';
+import { Notes } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -42,21 +21,38 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.andWhere('note.replyId = :replyId', { replyId: ps.noteId })
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateVisibilityQuery(query, user);
 	if (user) generateMutedUserQuery(query, user);
 	if (user) generateBlockedUserQuery(query, user);
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	return await Notes.packMany(timeline, user);
 });
diff --git a/packages/backend/src/server/api/endpoints/notes/search-by-tag.ts b/packages/backend/src/server/api/endpoints/notes/search-by-tag.ts
index 87eaffe2f1..c6503eb057 100644
--- a/packages/backend/src/server/api/endpoints/notes/search-by-tag.ts
+++ b/packages/backend/src/server/api/endpoints/notes/search-by-tag.ts
@@ -1,60 +1,16 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Notes } from '@/models/index';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
+import define from '../../define.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { Notes } from '@/models/index.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
 import { Brackets } from 'typeorm';
-import { safeForSql } from '@/misc/safe-for-sql';
-import { normalizeForSearch } from '@/misc/normalize-for-search';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import { safeForSql } from '@/misc/safe-for-sql.js';
+import { normalizeForSearch } from '@/misc/normalize-for-search.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes', 'hashtags'],
 
-	params: {
-		tag: {
-			validator: $.optional.str,
-		},
-
-		query: {
-			validator: $.optional.arr($.arr($.str)),
-		},
-
-		reply: {
-			validator: $.optional.nullable.bool,
-			default: null,
-		},
-
-		renote: {
-			validator: $.optional.nullable.bool,
-			default: null,
-		},
-
-		withFiles: {
-			validator: $.optional.bool,
-		},
-
-		poll: {
-			validator: $.optional.nullable.bool,
-			default: null,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -66,14 +22,40 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		tag: { type: 'string' },
+		query: { type: 'array', items: {
+			type: 'array', items: {
+				type: 'string',
+			},
+		} },
+		reply: { type: 'boolean', nullable: true, default: null },
+		renote: { type: 'boolean', nullable: true, default: null },
+		withFiles: { type: 'boolean' },
+		poll: { type: 'boolean', nullable: true, default: null },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateVisibilityQuery(query, me);
 	if (me) generateMutedUserQuery(query, me);
@@ -129,7 +111,7 @@ export default define(meta, async (ps, me) => {
 	}
 
 	// Search notes
-	const notes = await query.take(ps.limit!).getMany();
+	const notes = await query.take(ps.limit).getMany();
 
 	return await Notes.packMany(notes, me);
 });
diff --git a/packages/backend/src/server/api/endpoints/notes/search.ts b/packages/backend/src/server/api/endpoints/notes/search.ts
index e75212b14b..e77892b150 100644
--- a/packages/backend/src/server/api/endpoints/notes/search.ts
+++ b/packages/backend/src/server/api/endpoints/notes/search.ts
@@ -1,54 +1,18 @@
-import $ from 'cafy';
-import es from '../../../../db/elasticsearch';
-import define from '../../define';
-import { Notes } from '@/models/index';
+import es from '../../../../db/elasticsearch.js';
+import define from '../../define.js';
+import { Notes } from '@/models/index.js';
 import { In } from 'typeorm';
-import { ID } from '@/misc/cafy-id';
-import config from '@/config/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import config from '@/config/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		query: {
-			validator: $.str,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		host: {
-			validator: $.optional.nullable.str,
-			default: undefined,
-		},
-
-		userId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-
-		channelId: {
-			validator: $.optional.nullable.type(ID),
-			default: null,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -63,8 +27,23 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		query: { type: 'string' },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+		host: { type: 'string', nullable: true },
+		userId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+		channelId: { type: 'string', format: 'misskey:id', nullable: true, default: null },
+	},
+	required: ['query'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	if (es == null) {
 		const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId);
 
@@ -77,16 +56,22 @@ export default define(meta, async (ps, me) => {
 		query
 			.andWhere('note.text ILIKE :q', { q: `%${ps.query}%` })
 			.innerJoinAndSelect('note.user', 'user')
+			.leftJoinAndSelect('user.avatar', 'avatar')
+			.leftJoinAndSelect('user.banner', 'banner')
 			.leftJoinAndSelect('note.reply', 'reply')
 			.leftJoinAndSelect('note.renote', 'renote')
 			.leftJoinAndSelect('reply.user', 'replyUser')
-			.leftJoinAndSelect('renote.user', 'renoteUser');
+			.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+			.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+			.leftJoinAndSelect('renote.user', 'renoteUser')
+			.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+			.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 		generateVisibilityQuery(query, me);
 		if (me) generateMutedUserQuery(query, me);
 		if (me) generateBlockedUserQuery(query, me);
 
-		const notes = await query.take(ps.limit!).getMany();
+		const notes = await query.take(ps.limit).getMany();
 
 		return await Notes.packMany(notes, me);
 	} else {
@@ -115,7 +100,7 @@ export default define(meta, async (ps, me) => {
 		const result = await es.search({
 			index: config.elasticsearch.index || 'misskey_note',
 			body: {
-				size: ps.limit!,
+				size: ps.limit,
 				from: ps.offset,
 				query: {
 					bool: {
diff --git a/packages/backend/src/server/api/endpoints/notes/show.ts b/packages/backend/src/server/api/endpoints/notes/show.ts
index feb94be1a1..d6692923c3 100644
--- a/packages/backend/src/server/api/endpoints/notes/show.ts
+++ b/packages/backend/src/server/api/endpoints/notes/show.ts
@@ -1,21 +1,13 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
-import { Notes } from '@/models/index';
+import define from '../../define.js';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
+import { Notes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -31,8 +23,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/state.ts b/packages/backend/src/server/api/endpoints/notes/state.ts
index c3e9090bbf..6fdb8e88fb 100644
--- a/packages/backend/src/server/api/endpoints/notes/state.ts
+++ b/packages/backend/src/server/api/endpoints/notes/state.ts
@@ -1,19 +1,11 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { NoteFavorites, Notes, NoteThreadMutings, NoteWatchings } from '@/models/index';
+import define from '../../define.js';
+import { NoteFavorites, Notes, NoteThreadMutings, NoteWatchings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: true,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -34,8 +26,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await Notes.findOneOrFail(ps.noteId);
 
 	const [favorite, watching, threadMuting] = await Promise.all([
diff --git a/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts b/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts
index a8b50d90f6..e48a2cf576 100644
--- a/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/thread-muting/create.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { getNote } from '../../../common/getters';
-import { ApiError } from '../../../error';
-import { Notes, NoteThreadMutings } from '@/models';
-import { genId } from '@/misc/gen-id';
-import readNote from '@/services/note/read';
+import define from '../../../define.js';
+import { getNote } from '../../../common/getters.js';
+import { ApiError } from '../../../error.js';
+import { Notes, NoteThreadMutings } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import readNote from '@/services/note/read.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -14,12 +12,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -29,8 +21,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/thread-muting/delete.ts b/packages/backend/src/server/api/endpoints/notes/thread-muting/delete.ts
index f76b526ce1..4fb3137a5e 100644
--- a/packages/backend/src/server/api/endpoints/notes/thread-muting/delete.ts
+++ b/packages/backend/src/server/api/endpoints/notes/thread-muting/delete.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { getNote } from '../../../common/getters';
-import { ApiError } from '../../../error';
-import { NoteThreadMutings } from '@/models';
+import define from '../../../define.js';
+import { getNote } from '../../../common/getters.js';
+import { ApiError } from '../../../error.js';
+import { NoteThreadMutings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/timeline.ts b/packages/backend/src/server/api/endpoints/notes/timeline.ts
index f8cd083249..fde66b241b 100644
--- a/packages/backend/src/server/api/endpoints/notes/timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/timeline.ts
@@ -1,65 +1,21 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { Notes, Followings } from '@/models/index';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
-import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query';
-import { activeUsersChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { Notes, Followings } from '@/models/index.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
+import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query.js';
+import { activeUsersChart } from '@/services/chart/index.js';
 import { Brackets } from 'typeorm';
-import { generateRepliesQuery } from '../../common/generate-replies-query';
-import { generateMutedNoteQuery } from '../../common/generate-muted-note-query';
-import { generateChannelQuery } from '../../common/generate-channel-query';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
+import { generateRepliesQuery } from '../../common/generate-replies-query.js';
+import { generateMutedNoteQuery } from '../../common/generate-muted-note-query.js';
+import { generateChannelQuery } from '../../common/generate-channel-query.js';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: true,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-
-		includeMyRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeRenotedMyNotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeLocalRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		withFiles: {
-			validator: $.optional.bool,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -71,8 +27,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+		includeMyRenotes: { type: 'boolean', default: true },
+		includeRenotedMyNotes: { type: 'boolean', default: true },
+		includeLocalRenotes: { type: 'boolean', default: true },
+		withFiles: { type: 'boolean' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const hasFollowing = (await Followings.count({
 		where: {
 			followerId: user.id,
@@ -92,10 +64,16 @@ export default define(meta, async (ps, user) => {
 			if (hasFollowing) qb.orWhere(`note.userId IN (${ followingQuery.getQuery() })`);
 		}))
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
 		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner')
 		.setParameters(followingQuery.getParameters());
 
 	generateChannelQuery(query, user);
@@ -141,7 +119,7 @@ export default define(meta, async (ps, user) => {
 	}
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	process.nextTick(() => {
 		if (user) {
diff --git a/packages/backend/src/server/api/endpoints/notes/translate.ts b/packages/backend/src/server/api/endpoints/notes/translate.ts
index ed069cb75a..068df6940b 100644
--- a/packages/backend/src/server/api/endpoints/notes/translate.ts
+++ b/packages/backend/src/server/api/endpoints/notes/translate.ts
@@ -1,29 +1,18 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
+import define from '../../define.js';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
 import fetch from 'node-fetch';
-import config from '@/config/index';
-import { getAgentByUrl } from '@/misc/fetch';
-import { URLSearchParams } from 'url';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Notes } from '@/models';
+import config from '@/config/index.js';
+import { getAgentByUrl } from '@/misc/fetch.js';
+import { URLSearchParams } from 'node:url';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Notes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: false,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-		targetLang: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -38,8 +27,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+		targetLang: { type: 'string' },
+	},
+	required: ['noteId', 'targetLang'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/unrenote.ts b/packages/backend/src/server/api/endpoints/notes/unrenote.ts
index 8db543d328..a9aadba338 100644
--- a/packages/backend/src/server/api/endpoints/notes/unrenote.ts
+++ b/packages/backend/src/server/api/endpoints/notes/unrenote.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import deleteNote from '@/services/note/delete';
-import define from '../../define';
+import deleteNote from '@/services/note/delete.js';
+import define from '../../define.js';
 import ms from 'ms';
-import { getNote } from '../../common/getters';
-import { ApiError } from '../../error';
-import { Notes, Users } from '@/models/index';
+import { getNote } from '../../common/getters.js';
+import { ApiError } from '../../error.js';
+import { Notes, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -20,12 +18,6 @@ export const meta = {
 		minInterval: ms('1sec'),
 	},
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -35,8 +27,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts b/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
index 3512fb3638..0829d0e4c1 100644
--- a/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
+++ b/packages/backend/src/server/api/endpoints/notes/user-list-timeline.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { UserLists, UserListJoinings, Notes } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { activeUsersChart } from '@/services/chart/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { UserLists, UserListJoinings, Notes } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { activeUsersChart } from '@/services/chart/index.js';
 import { Brackets } from 'typeorm';
 
 export const meta = {
@@ -13,52 +11,6 @@ export const meta = {
 
 	requireCredential: true,
 
-	params: {
-		listId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-
-		includeMyRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeRenotedMyNotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		includeLocalRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		withFiles: {
-			validator: $.optional.bool,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -78,8 +30,25 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		listId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+		includeMyRenotes: { type: 'boolean', default: true },
+		includeRenotedMyNotes: { type: 'boolean', default: true },
+		includeLocalRenotes: { type: 'boolean', default: true },
+		withFiles: { type: 'boolean' },
+	},
+	required: ['listId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const list = await UserLists.findOne({
 		id: ps.listId,
 		userId: user.id,
@@ -97,10 +66,16 @@ export default define(meta, async (ps, user) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId)
 		.andWhere(`note.userId IN (${ listQuery.getQuery() })`)
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
 		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner')
 		.setParameters(listQuery.getParameters());
 
 	generateVisibilityQuery(query, user);
@@ -140,7 +115,7 @@ export default define(meta, async (ps, user) => {
 	}
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	activeUsersChart.read(user);
 
diff --git a/packages/backend/src/server/api/endpoints/notes/watching/create.ts b/packages/backend/src/server/api/endpoints/notes/watching/create.ts
index 6433c6bc2a..8fdf84624e 100644
--- a/packages/backend/src/server/api/endpoints/notes/watching/create.ts
+++ b/packages/backend/src/server/api/endpoints/notes/watching/create.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import watch from '@/services/note/watch';
-import { getNote } from '../../../common/getters';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import watch from '@/services/note/watch.js';
+import { getNote } from '../../../common/getters.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notes/watching/delete.ts b/packages/backend/src/server/api/endpoints/notes/watching/delete.ts
index 3e9faa2b23..d58f09797c 100644
--- a/packages/backend/src/server/api/endpoints/notes/watching/delete.ts
+++ b/packages/backend/src/server/api/endpoints/notes/watching/delete.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import unwatch from '@/services/note/unwatch';
-import { getNote } from '../../../common/getters';
-import { ApiError } from '../../../error';
+import define from '../../../define.js';
+import unwatch from '@/services/note/unwatch.js';
+import { getNote } from '../../../common/getters.js';
+import { ApiError } from '../../../error.js';
 
 export const meta = {
 	tags: ['notes'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -27,8 +19,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/notifications/create.ts b/packages/backend/src/server/api/endpoints/notifications/create.ts
index bd8a7ba1b7..b339c8723d 100644
--- a/packages/backend/src/server/api/endpoints/notifications/create.ts
+++ b/packages/backend/src/server/api/endpoints/notifications/create.ts
@@ -1,6 +1,5 @@
-import $ from 'cafy';
-import define from '../../define';
-import { createNotification } from '@/services/create-notification';
+import define from '../../define.js';
+import { createNotification } from '@/services/create-notification.js';
 
 export const meta = {
 	tags: ['notifications'],
@@ -9,26 +8,22 @@ export const meta = {
 
 	kind: 'write:notifications',
 
-	params: {
-		body: {
-			validator: $.str,
-		},
-
-		header: {
-			validator: $.optional.nullable.str,
-		},
-
-		icon: {
-			validator: $.optional.nullable.str,
-		},
+	errors: {
 	},
+} as const;
 
-	errors: {
+export const paramDef = {
+	type: 'object',
+	properties: {
+		body: { type: 'string' },
+		header: { type: 'string', nullable: true },
+		icon: { type: 'string', nullable: true },
 	},
+	required: ['body'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user, token) => {
+export default define(meta, paramDef, async (ps, user, token) => {
 	createNotification(user.id, 'app', {
 		appAccessTokenId: token ? token.id : null,
 		customBody: ps.body,
diff --git a/packages/backend/src/server/api/endpoints/notifications/mark-all-as-read.ts b/packages/backend/src/server/api/endpoints/notifications/mark-all-as-read.ts
index 4cec38a95d..abefe07be6 100644
--- a/packages/backend/src/server/api/endpoints/notifications/mark-all-as-read.ts
+++ b/packages/backend/src/server/api/endpoints/notifications/mark-all-as-read.ts
@@ -1,6 +1,6 @@
-import { publishMainStream } from '@/services/stream';
-import define from '../../define';
-import { Notifications } from '@/models/index';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../../define.js';
+import { Notifications } from '@/models/index.js';
 
 export const meta = {
 	tags: ['notifications', 'account'],
@@ -10,8 +10,14 @@ export const meta = {
 	kind: 'write:notifications',
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Update documents
 	await Notifications.update({
 		notifieeId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/notifications/read.ts b/packages/backend/src/server/api/endpoints/notifications/read.ts
index 7e23bc234d..34f4c155fa 100644
--- a/packages/backend/src/server/api/endpoints/notifications/read.ts
+++ b/packages/backend/src/server/api/endpoints/notifications/read.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { publishMainStream } from '@/services/stream';
-import define from '../../define';
-import { Notifications } from '@/models/index';
-import { readNotification } from '../../common/read-notification';
-import { ApiError } from '../../error';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../../define.js';
+import { Notifications } from '@/models/index.js';
+import { readNotification } from '../../common/read-notification.js';
+import { ApiError } from '../../error.js';
 
 export const meta = {
 	tags: ['notifications', 'account'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:notifications',
 
-	params: {
-		notificationId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNotification: {
 			message: 'No such notification.',
@@ -28,8 +20,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		notificationId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['notificationId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const notification = await Notifications.findOne({
 		notifieeId: user.id,
 		id: ps.notificationId,
diff --git a/packages/backend/src/server/api/endpoints/page-push.ts b/packages/backend/src/server/api/endpoints/page-push.ts
index 61c0160f83..acaa118470 100644
--- a/packages/backend/src/server/api/endpoints/page-push.ts
+++ b/packages/backend/src/server/api/endpoints/page-push.ts
@@ -1,28 +1,12 @@
-import $ from 'cafy';
-import define from '../define';
-import { ID } from '@/misc/cafy-id';
-import { publishMainStream } from '@/services/stream';
-import { Users, Pages } from '@/models/index';
-import { ApiError } from '../error';
+import define from '../define.js';
+import { publishMainStream } from '@/services/stream.js';
+import { Users, Pages } from '@/models/index.js';
+import { ApiError } from '../error.js';
 
 export const meta = {
 	requireCredential: true,
 	secure: true,
 
-	params: {
-		pageId: {
-			validator: $.type(ID),
-		},
-
-		event: {
-			validator: $.str,
-		},
-
-		var: {
-			validator: $.optional.nullable.any,
-		},
-	},
-
 	errors: {
 		noSuchPage: {
 			message: 'No such page.',
@@ -32,8 +16,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		pageId: { type: 'string', format: 'misskey:id' },
+		event: { type: 'string' },
+		var: {},
+	},
+	required: ['pageId', 'event'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const page = await Pages.findOne(ps.pageId);
 	if (page == null) {
 		throw new ApiError(meta.errors.noSuchPage);
diff --git a/packages/backend/src/server/api/endpoints/pages/create.ts b/packages/backend/src/server/api/endpoints/pages/create.ts
index 7ee50fbdfa..7cac530606 100644
--- a/packages/backend/src/server/api/endpoints/pages/create.ts
+++ b/packages/backend/src/server/api/endpoints/pages/create.ts
@@ -1,11 +1,9 @@
-import $ from 'cafy';
 import ms from 'ms';
-import define from '../../define';
-import { ID } from '@/misc/cafy-id';
-import { Pages, DriveFiles } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { Page } from '@/models/entities/page';
-import { ApiError } from '../../error';
+import define from '../../define.js';
+import { Pages, DriveFiles } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { Page } from '@/models/entities/page.js';
+import { ApiError } from '../../error.js';
 
 export const meta = {
 	tags: ['pages'],
@@ -19,51 +17,6 @@ export const meta = {
 		max: 300,
 	},
 
-	params: {
-		title: {
-			validator: $.str,
-		},
-
-		name: {
-			validator: $.str.min(1),
-		},
-
-		summary: {
-			validator: $.optional.nullable.str,
-		},
-
-		content: {
-			validator: $.arr($.obj()),
-		},
-
-		variables: {
-			validator: $.arr($.obj()),
-		},
-
-		script: {
-			validator: $.str,
-		},
-
-		eyeCatchingImageId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		font: {
-			validator: $.optional.str.or(['serif', 'sans-serif']),
-			default: 'sans-serif',
-		},
-
-		alignCenter: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		hideTitleWhenPinned: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -84,8 +37,29 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		title: { type: 'string' },
+		name: { type: 'string', minLength: 1 },
+		summary: { type: 'string', nullable: true },
+		content: { type: 'array', items: {
+			type: 'object', additionalProperties: true,
+		} },
+		variables: { type: 'array', items: {
+			type: 'object', additionalProperties: true,
+		} },
+		script: { type: 'string' },
+		eyeCatchingImageId: { type: 'string', format: 'misskey:id', nullable: true },
+		font: { type: 'string', enum: ['serif', 'sans-serif'], default: "sans-serif" },
+		alignCenter: { type: 'boolean', default: false },
+		hideTitleWhenPinned: { type: 'boolean', default: false },
+	},
+	required: ['title', 'name', 'content', 'variables', 'script'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let eyeCatchingImage = null;
 	if (ps.eyeCatchingImageId != null) {
 		eyeCatchingImage = await DriveFiles.findOne({
diff --git a/packages/backend/src/server/api/endpoints/pages/delete.ts b/packages/backend/src/server/api/endpoints/pages/delete.ts
index aeda823e52..ddf691f53c 100644
--- a/packages/backend/src/server/api/endpoints/pages/delete.ts
+++ b/packages/backend/src/server/api/endpoints/pages/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Pages } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Pages } from '@/models/index.js';
 
 export const meta = {
 	tags: ['pages'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:pages',
 
-	params: {
-		pageId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPage: {
 			message: 'No such page.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		pageId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['pageId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const page = await Pages.findOne(ps.pageId);
 	if (page == null) {
 		throw new ApiError(meta.errors.noSuchPage);
diff --git a/packages/backend/src/server/api/endpoints/pages/featured.ts b/packages/backend/src/server/api/endpoints/pages/featured.ts
index 7f0d58b350..eeb6d509ca 100644
--- a/packages/backend/src/server/api/endpoints/pages/featured.ts
+++ b/packages/backend/src/server/api/endpoints/pages/featured.ts
@@ -1,5 +1,5 @@
-import define from '../../define';
-import { Pages } from '@/models/index';
+import define from '../../define.js';
+import { Pages } from '@/models/index.js';
 
 export const meta = {
 	tags: ['pages'],
@@ -17,8 +17,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Pages.createQueryBuilder('page')
 		.where('page.visibility = \'public\'')
 		.andWhere('page.likedCount > 0')
diff --git a/packages/backend/src/server/api/endpoints/pages/like.ts b/packages/backend/src/server/api/endpoints/pages/like.ts
index c479f637a9..cab78e576c 100644
--- a/packages/backend/src/server/api/endpoints/pages/like.ts
+++ b/packages/backend/src/server/api/endpoints/pages/like.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Pages, PageLikes } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Pages, PageLikes } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['pages'],
@@ -12,12 +10,6 @@ export const meta = {
 
 	kind: 'write:page-likes',
 
-	params: {
-		pageId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPage: {
 			message: 'No such page.',
@@ -39,8 +31,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		pageId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['pageId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const page = await Pages.findOne(ps.pageId);
 	if (page == null) {
 		throw new ApiError(meta.errors.noSuchPage);
diff --git a/packages/backend/src/server/api/endpoints/pages/show.ts b/packages/backend/src/server/api/endpoints/pages/show.ts
index 5cda5386d5..4e3facae5b 100644
--- a/packages/backend/src/server/api/endpoints/pages/show.ts
+++ b/packages/backend/src/server/api/endpoints/pages/show.ts
@@ -1,29 +1,13 @@
-import $ from 'cafy';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Pages, Users } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
-import { Page } from '@/models/entities/page';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Pages, Users } from '@/models/index.js';
+import { Page } from '@/models/entities/page.js';
 
 export const meta = {
 	tags: ['pages'],
 
 	requireCredential: false,
 
-	params: {
-		pageId: {
-			validator: $.optional.type(ID),
-		},
-
-		name: {
-			validator: $.optional.str,
-		},
-
-		username: {
-			validator: $.optional.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -39,8 +23,18 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		pageId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string' },
+		username: { type: 'string' },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	let page: Page | undefined;
 
 	if (ps.pageId) {
diff --git a/packages/backend/src/server/api/endpoints/pages/unlike.ts b/packages/backend/src/server/api/endpoints/pages/unlike.ts
index cca5e5b5a9..31cd1a3359 100644
--- a/packages/backend/src/server/api/endpoints/pages/unlike.ts
+++ b/packages/backend/src/server/api/endpoints/pages/unlike.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Pages, PageLikes } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Pages, PageLikes } from '@/models/index.js';
 
 export const meta = {
 	tags: ['pages'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:page-likes',
 
-	params: {
-		pageId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchPage: {
 			message: 'No such page.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		pageId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['pageId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const page = await Pages.findOne(ps.pageId);
 	if (page == null) {
 		throw new ApiError(meta.errors.noSuchPage);
diff --git a/packages/backend/src/server/api/endpoints/pages/update.ts b/packages/backend/src/server/api/endpoints/pages/update.ts
index 991085ee09..24c8f467e6 100644
--- a/packages/backend/src/server/api/endpoints/pages/update.ts
+++ b/packages/backend/src/server/api/endpoints/pages/update.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
 import ms from 'ms';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Pages, DriveFiles } from '@/models/index';
-import { ID } from '@/misc/cafy-id';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Pages, DriveFiles } from '@/models/index.js';
 import { Not } from 'typeorm';
 
 export const meta = {
@@ -18,52 +16,6 @@ export const meta = {
 		max: 300,
 	},
 
-	params: {
-		pageId: {
-			validator: $.type(ID),
-		},
-
-		title: {
-			validator: $.str,
-		},
-
-		name: {
-			validator: $.str.min(1),
-		},
-
-		summary: {
-			validator: $.optional.nullable.str,
-		},
-
-		content: {
-			validator: $.arr($.obj()),
-		},
-
-		variables: {
-			validator: $.arr($.obj()),
-		},
-
-		script: {
-			validator: $.str,
-		},
-
-		eyeCatchingImageId: {
-			validator: $.optional.nullable.type(ID),
-		},
-
-		font: {
-			validator: $.optional.str.or(['serif', 'sans-serif']),
-		},
-
-		alignCenter: {
-			validator: $.optional.bool,
-		},
-
-		hideTitleWhenPinned: {
-			validator: $.optional.bool,
-		},
-	},
-
 	errors: {
 		noSuchPage: {
 			message: 'No such page.',
@@ -90,8 +42,30 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		pageId: { type: 'string', format: 'misskey:id' },
+		title: { type: 'string' },
+		name: { type: 'string', minLength: 1 },
+		summary: { type: 'string', nullable: true },
+		content: { type: 'array', items: {
+			type: 'object', additionalProperties: true,
+		} },
+		variables: { type: 'array', items: {
+			type: 'object', additionalProperties: true,
+		} },
+		script: { type: 'string' },
+		eyeCatchingImageId: { type: 'string', format: 'misskey:id', nullable: true },
+		font: { type: 'string', enum: ['serif', 'sans-serif'] },
+		alignCenter: { type: 'boolean' },
+		hideTitleWhenPinned: { type: 'boolean' },
+	},
+	required: ['pageId', 'title', 'name', 'content', 'variables', 'script'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const page = await Pages.findOne(ps.pageId);
 	if (page == null) {
 		throw new ApiError(meta.errors.noSuchPage);
diff --git a/packages/backend/src/server/api/endpoints/ping.ts b/packages/backend/src/server/api/endpoints/ping.ts
index 3eab70ae2e..2891a0860a 100644
--- a/packages/backend/src/server/api/endpoints/ping.ts
+++ b/packages/backend/src/server/api/endpoints/ping.ts
@@ -1,13 +1,10 @@
-import define from '../define';
+import define from '../define.js';
 
 export const meta = {
 	requireCredential: false,
 
 	tags: ['meta'],
 
-	params: {
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -20,8 +17,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	return {
 		pong: Date.now(),
 	};
diff --git a/packages/backend/src/server/api/endpoints/pinned-users.ts b/packages/backend/src/server/api/endpoints/pinned-users.ts
index ff0e22555f..1d26ab266e 100644
--- a/packages/backend/src/server/api/endpoints/pinned-users.ts
+++ b/packages/backend/src/server/api/endpoints/pinned-users.ts
@@ -1,17 +1,14 @@
-import define from '../define';
-import { Users } from '@/models/index';
-import { fetchMeta } from '@/misc/fetch-meta';
-import * as Acct from 'misskey-js/built/acct';
-import { User } from '@/models/entities/user';
+import define from '../define.js';
+import { Users } from '@/models/index.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import * as Acct from '@/misc/acct.js';
+import { User } from '@/models/entities/user.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -23,8 +20,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const meta = await fetchMeta();
 
 	const users = await Promise.all(meta.pinnedUsers.map(acct => Users.findOne(Acct.parse(acct))));
diff --git a/packages/backend/src/server/api/endpoints/promo/read.ts b/packages/backend/src/server/api/endpoints/promo/read.ts
index 8d8c60d755..ea34ca3aad 100644
--- a/packages/backend/src/server/api/endpoints/promo/read.ts
+++ b/packages/backend/src/server/api/endpoints/promo/read.ts
@@ -1,22 +1,14 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getNote } from '../../common/getters';
-import { PromoReads } from '@/models/index';
-import { genId } from '@/misc/gen-id';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getNote } from '../../common/getters.js';
+import { PromoReads } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
 
 export const meta = {
 	tags: ['notes'],
 
 	requireCredential: true,
 
-	params: {
-		noteId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchNote: {
 			message: 'No such note.',
@@ -26,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		noteId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['noteId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const note = await getNote(ps.noteId).catch(e => {
 		if (e.id === '9725d0ce-ba28-4dde-95a7-2cbb2c15de24') throw new ApiError(meta.errors.noSuchNote);
 		throw e;
diff --git a/packages/backend/src/server/api/endpoints/request-reset-password.ts b/packages/backend/src/server/api/endpoints/request-reset-password.ts
index af1aeb4311..18cd98b164 100644
--- a/packages/backend/src/server/api/endpoints/request-reset-password.ts
+++ b/packages/backend/src/server/api/endpoints/request-reset-password.ts
@@ -1,13 +1,12 @@
-import $ from 'cafy';
-import { publishMainStream } from '@/services/stream';
-import define from '../define';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../define.js';
 import rndstr from 'rndstr';
-import config from '@/config/index';
+import config from '@/config/index.js';
 import ms from 'ms';
-import { Users, UserProfiles, PasswordResetRequests } from '@/models/index';
-import { sendEmail } from '@/services/send-email';
-import { ApiError } from '../error';
-import { genId } from '@/misc/gen-id';
+import { Users, UserProfiles, PasswordResetRequests } from '@/models/index.js';
+import { sendEmail } from '@/services/send-email.js';
+import { ApiError } from '../error.js';
+import { genId } from '@/misc/gen-id.js';
 import { IsNull } from 'typeorm';
 
 export const meta = {
@@ -18,23 +17,22 @@ export const meta = {
 		max: 3,
 	},
 
-	params: {
-		username: {
-			validator: $.str,
-		},
+	errors: {
 
-		email: {
-			validator: $.str,
-		},
 	},
+} as const;
 
-	errors: {
-
+export const paramDef = {
+	type: 'object',
+	properties: {
+		username: { type: 'string' },
+		email: { type: 'string' },
 	},
+	required: ['username', 'email'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	const user = await Users.findOne({
 		usernameLower: ps.username.toLowerCase(),
 		host: IsNull(),
diff --git a/packages/backend/src/server/api/endpoints/reset-db.ts b/packages/backend/src/server/api/endpoints/reset-db.ts
index e99dc9db15..dbe64e9a13 100644
--- a/packages/backend/src/server/api/endpoints/reset-db.ts
+++ b/packages/backend/src/server/api/endpoints/reset-db.ts
@@ -1,21 +1,23 @@
-import $ from 'cafy';
-import define from '../define';
-import { ApiError } from '../error';
-import { resetDb } from '@/db/postgre';
+import define from '../define.js';
+import { ApiError } from '../error.js';
+import { resetDb } from '@/db/postgre.js';
 
 export const meta = {
 	requireCredential: false,
 
-	params: {
-	},
-
 	errors: {
 
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	if (process.env.NODE_ENV !== 'test') throw 'NODE_ENV is not a test';
 
 	await resetDb();
diff --git a/packages/backend/src/server/api/endpoints/reset-password.ts b/packages/backend/src/server/api/endpoints/reset-password.ts
index a7366584b1..3abf232af0 100644
--- a/packages/backend/src/server/api/endpoints/reset-password.ts
+++ b/packages/backend/src/server/api/endpoints/reset-password.ts
@@ -1,30 +1,28 @@
-import $ from 'cafy';
-import * as bcrypt from 'bcryptjs';
-import { publishMainStream } from '@/services/stream';
-import define from '../define';
-import { Users, UserProfiles, PasswordResetRequests } from '@/models/index';
-import { ApiError } from '../error';
+import bcrypt from 'bcryptjs';
+import { publishMainStream } from '@/services/stream.js';
+import define from '../define.js';
+import { Users, UserProfiles, PasswordResetRequests } from '@/models/index.js';
+import { ApiError } from '../error.js';
 
 export const meta = {
 	requireCredential: false,
 
-	params: {
-		token: {
-			validator: $.str,
-		},
+	errors: {
 
-		password: {
-			validator: $.str,
-		},
 	},
+} as const;
 
-	errors: {
-
+export const paramDef = {
+	type: 'object',
+	properties: {
+		token: { type: 'string' },
+		password: { type: 'string' },
 	},
+	required: ['token', 'password'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const req = await PasswordResetRequests.findOneOrFail({
 		token: ps.token,
 	});
diff --git a/packages/backend/src/server/api/endpoints/server-info.ts b/packages/backend/src/server/api/endpoints/server-info.ts
index 1ad2c54ab5..99f3730e97 100644
--- a/packages/backend/src/server/api/endpoints/server-info.ts
+++ b/packages/backend/src/server/api/endpoints/server-info.ts
@@ -1,21 +1,21 @@
-import * as os from 'os';
-import * as si from 'systeminformation';
-import define from '../define';
+import * as os from 'node:os';
+import si from 'systeminformation';
+import define from '../define.js';
 
 export const meta = {
 	requireCredential: false,
 
-	desc: {
-	},
-
 	tags: ['meta'],
+} as const;
 
-	params: {
-	},
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const memStats = await si.mem();
 	const fsStats = await si.fsSize();
 
diff --git a/packages/backend/src/server/api/endpoints/stats.ts b/packages/backend/src/server/api/endpoints/stats.ts
index 82b0bb3291..92fea4de6a 100644
--- a/packages/backend/src/server/api/endpoints/stats.ts
+++ b/packages/backend/src/server/api/endpoints/stats.ts
@@ -1,15 +1,12 @@
-import define from '../define';
-import { Instances, NoteReactions, Notes, Users } from '@/models/index';
-import { } from '@/services/chart/index';
+import define from '../define.js';
+import { Instances, NoteReactions, Notes, Users } from '@/models/index.js';
+import { } from '@/services/chart/index.js';
 
 export const meta = {
 	requireCredential: false,
 
 	tags: ['meta'],
 
-	params: {
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -46,8 +43,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async () => {
+export default define(meta, paramDef, async () => {
 	const [
 		notesCount,
 		originalNotesCount,
diff --git a/packages/backend/src/server/api/endpoints/sw/register.ts b/packages/backend/src/server/api/endpoints/sw/register.ts
index ae3e9ce77a..6c7714e19b 100644
--- a/packages/backend/src/server/api/endpoints/sw/register.ts
+++ b/packages/backend/src/server/api/endpoints/sw/register.ts
@@ -1,47 +1,42 @@
-import $ from 'cafy';
-import define from '../../define';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { genId } from '@/misc/gen-id';
-import { SwSubscriptions } from '@/models/index';
+import define from '../../define.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { genId } from '@/misc/gen-id.js';
+import { SwSubscriptions } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
 
 	requireCredential: true,
 
-	params: {
-		endpoint: {
-			validator: $.str,
-		},
-
-		auth: {
-			validator: $.str,
-		},
-
-		publickey: {
-			validator: $.str,
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
 		properties: {
 			state: {
 				type: 'string',
-				optional: false, nullable: false,
+				optional: true, nullable: false,
 				enum: ['already-subscribed', 'subscribed'],
 			},
 			key: {
 				type: 'string',
-				optional: false, nullable: false,
+				optional: false, nullable: true,
 			},
 		},
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		endpoint: { type: 'string' },
+		auth: { type: 'string' },
+		publickey: { type: 'string' },
+	},
+	required: ['endpoint', 'auth', 'publickey'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// if already subscribed
 	const exist = await SwSubscriptions.findOne({
 		userId: user.id,
@@ -54,7 +49,7 @@ export default define(meta, async (ps, user) => {
 
 	if (exist != null) {
 		return {
-			state: 'already-subscribed',
+			state: 'already-subscribed' as const,
 			key: instance.swPublicKey,
 		};
 	}
@@ -69,7 +64,7 @@ export default define(meta, async (ps, user) => {
 	});
 
 	return {
-		state: 'subscribed',
+		state: 'subscribed' as const,
 		key: instance.swPublicKey,
 	};
 });
diff --git a/packages/backend/src/server/api/endpoints/sw/unregister.ts b/packages/backend/src/server/api/endpoints/sw/unregister.ts
index 6f569e9417..9748f2a222 100644
--- a/packages/backend/src/server/api/endpoints/sw/unregister.ts
+++ b/packages/backend/src/server/api/endpoints/sw/unregister.ts
@@ -1,21 +1,22 @@
-import $ from 'cafy';
-import define from '../../define';
-import { SwSubscriptions } from '../../../../models';
+import define from '../../define.js';
+import { SwSubscriptions } from '@/models/index.js';
 
 export const meta = {
 	tags: ['account'],
 
 	requireCredential: true,
+} as const;
 
-	params: {
-		endpoint: {
-			validator: $.str,
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		endpoint: { type: 'string' },
 	},
+	required: ['endpoint'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	await SwSubscriptions.delete({
 		userId: user.id,
 		endpoint: ps.endpoint,
diff --git a/packages/backend/src/server/api/endpoints/test.ts b/packages/backend/src/server/api/endpoints/test.ts
new file mode 100644
index 0000000000..256da1a66f
--- /dev/null
+++ b/packages/backend/src/server/api/endpoints/test.ts
@@ -0,0 +1,22 @@
+import define from '../define.js';
+
+export const meta = {
+	requireCredential: false,
+} as const;
+
+export const paramDef = {
+	type: 'object',
+	properties: {
+		required: { type: 'boolean' },
+		string: { type: 'string' },
+		default: { type: 'string', default: 'hello' },
+		nullableDefault: { type: 'string', nullable: true, default: 'hello' },
+		id: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['required'],
+} as const;
+
+// eslint-disable-next-line import/no-default-export
+export default define(meta, paramDef, async (ps, me) => {
+	return ps;
+});
diff --git a/packages/backend/src/server/api/endpoints/username/available.ts b/packages/backend/src/server/api/endpoints/username/available.ts
index 74120fc406..5a1c4128ab 100644
--- a/packages/backend/src/server/api/endpoints/username/available.ts
+++ b/packages/backend/src/server/api/endpoints/username/available.ts
@@ -1,18 +1,11 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Users, UsedUsernames } from '@/models/index';
+import define from '../../define.js';
+import { Users, UsedUsernames } from '@/models/index.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		username: {
-			validator: $.use(Users.validateLocalUsername),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -25,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		username: Users.localUsernameSchema,
+	},
+	required: ['username'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps) => {
+export default define(meta, paramDef, async (ps) => {
 	// Get exist
 	const exist = await Users.count({
 		host: null,
diff --git a/packages/backend/src/server/api/endpoints/users.ts b/packages/backend/src/server/api/endpoints/users.ts
index 6b11ec0f01..10527d15cc 100644
--- a/packages/backend/src/server/api/endpoints/users.ts
+++ b/packages/backend/src/server/api/endpoints/users.ts
@@ -1,57 +1,13 @@
-import $ from 'cafy';
-import define from '../define';
-import { Users } from '@/models/index';
-import { generateMutedUserQueryForUsers } from '../common/generate-muted-user-query';
-import { generateBlockQueryForUsers } from '../common/generate-block-query';
+import define from '../define.js';
+import { Users } from '@/models/index.js';
+import { generateMutedUserQueryForUsers } from '../common/generate-muted-user-query.js';
+import { generateBlockQueryForUsers } from '../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-
-		sort: {
-			validator: $.optional.str.or([
-				'+follower',
-				'-follower',
-				'+createdAt',
-				'-createdAt',
-				'+updatedAt',
-				'-updatedAt',
-			]),
-		},
-
-		state: {
-			validator: $.optional.str.or([
-				'all',
-				'admin',
-				'moderator',
-				'adminOrModerator',
-				'alive',
-			]),
-			default: 'all',
-		},
-
-		origin: {
-			validator: $.optional.str.or([
-				'combined',
-				'local',
-				'remote',
-			]),
-			default: 'local',
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -63,8 +19,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+		sort: { type: 'string', enum: ['+follower', '-follower', '+createdAt', '-createdAt', '+updatedAt', '-updatedAt'] },
+		state: { type: 'string', enum: ['all', 'admin', 'moderator', 'adminOrModerator', 'alive'], default: "all" },
+		origin: { type: 'string', enum: ['combined', 'local', 'remote'], default: "local" },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Users.createQueryBuilder('user');
 	query.where('user.isExplorable = TRUE');
 
@@ -93,7 +61,7 @@ export default define(meta, async (ps, me) => {
 	if (me) generateMutedUserQueryForUsers(query, me);
 	if (me) generateBlockQueryForUsers(query, me);
 
-	query.take(ps.limit!);
+	query.take(ps.limit);
 	query.skip(ps.offset);
 
 	const users = await query.getMany();
diff --git a/packages/backend/src/server/api/endpoints/users/clips.ts b/packages/backend/src/server/api/endpoints/users/clips.ts
index d4152fbf50..424c594749 100644
--- a/packages/backend/src/server/api/endpoints/users/clips.ts
+++ b/packages/backend/src/server/api/endpoints/users/clips.ts
@@ -1,40 +1,30 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Clips } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Clips } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['users', 'clips'],
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Clips.createQueryBuilder('clip'), ps.sinceId, ps.untilId)
 		.andWhere(`clip.userId = :userId`, { userId: ps.userId })
 		.andWhere('clip.isPublic = true');
 
 	const clips = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Clips.packMany(clips);
diff --git a/packages/backend/src/server/api/endpoints/users/followers.ts b/packages/backend/src/server/api/endpoints/users/followers.ts
index 6214ab40ba..1e104b6bcc 100644
--- a/packages/backend/src/server/api/endpoints/users/followers.ts
+++ b/packages/backend/src/server/api/endpoints/users/followers.ts
@@ -1,43 +1,14 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Users, Followings, UserProfiles } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { toPunyNullable } from '@/misc/convert-host';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Users, Followings, UserProfiles } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { toPunyNullable } from '@/misc/convert-host.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		userId: {
-			validator: $.optional.type(ID),
-		},
-
-		username: {
-			validator: $.optional.str,
-		},
-
-		host: {
-			validator: $.optional.nullable.str,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -63,8 +34,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		username: { type: 'string' },
+		host: { type: 'string', nullable: true },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId != null
 		? { id: ps.userId }
 		: { usernameLower: ps.username!.toLowerCase(), host: toPunyNullable(ps.host) });
@@ -98,7 +82,7 @@ export default define(meta, async (ps, me) => {
 		.innerJoinAndSelect('following.follower', 'follower');
 
 	const followings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Followings.packMany(followings, me, { populateFollower: true });
diff --git a/packages/backend/src/server/api/endpoints/users/following.ts b/packages/backend/src/server/api/endpoints/users/following.ts
index 76112eab25..b0a1036c76 100644
--- a/packages/backend/src/server/api/endpoints/users/following.ts
+++ b/packages/backend/src/server/api/endpoints/users/following.ts
@@ -1,43 +1,14 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { Users, Followings, UserProfiles } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { toPunyNullable } from '@/misc/convert-host';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { Users, Followings, UserProfiles } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { toPunyNullable } from '@/misc/convert-host.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		userId: {
-			validator: $.optional.type(ID),
-		},
-
-		username: {
-			validator: $.optional.str,
-		},
-
-		host: {
-			validator: $.optional.nullable.str,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -63,8 +34,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		username: { type: 'string' },
+		host: { type: 'string', nullable: true },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId != null
 		? { id: ps.userId }
 		: { usernameLower: ps.username!.toLowerCase(), host: toPunyNullable(ps.host) });
@@ -98,7 +82,7 @@ export default define(meta, async (ps, me) => {
 		.innerJoinAndSelect('following.followee', 'followee');
 
 	const followings = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Followings.packMany(followings, me, { populateFollowee: true });
diff --git a/packages/backend/src/server/api/endpoints/users/gallery/posts.ts b/packages/backend/src/server/api/endpoints/users/gallery/posts.ts
index c5f08b4c94..d7c435256c 100644
--- a/packages/backend/src/server/api/endpoints/users/gallery/posts.ts
+++ b/packages/backend/src/server/api/endpoints/users/gallery/posts.ts
@@ -1,39 +1,29 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { GalleryPosts } from '@/models/index';
-import { makePaginationQuery } from '../../../common/make-pagination-query';
+import define from '../../../define.js';
+import { GalleryPosts } from '@/models/index.js';
+import { makePaginationQuery } from '../../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['users', 'gallery'],
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(GalleryPosts.createQueryBuilder('post'), ps.sinceId, ps.untilId)
 		.andWhere(`post.userId = :userId`, { userId: ps.userId });
 
 	const posts = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await GalleryPosts.packMany(posts, user);
diff --git a/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts b/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts
index d886d3355a..73cadc0df7 100644
--- a/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts
+++ b/packages/backend/src/server/api/endpoints/users/get-frequently-replied-users.ts
@@ -1,28 +1,15 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { maximum } from '@/prelude/array';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
+import define from '../../define.js';
+import { maximum } from '@/prelude/array.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
 import { Not, In, IsNull } from 'typeorm';
-import { Notes, Users } from '@/models/index';
+import { Notes, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -52,8 +39,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Lookup user
 	const user = await getUser(ps.userId).catch(e => {
 		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
@@ -104,7 +100,7 @@ export default define(meta, async (ps, me) => {
 	const repliedUsersSorted = Object.keys(repliedUsers).sort((a, b) => repliedUsers[b] - repliedUsers[a]);
 
 	// Extract top replied users
-	const topRepliedUsers = repliedUsersSorted.slice(0, ps.limit!);
+	const topRepliedUsers = repliedUsersSorted.slice(0, ps.limit);
 
 	// Make replies object (includes weights)
 	const repliesObj = await Promise.all(topRepliedUsers.map(async (user) => ({
diff --git a/packages/backend/src/server/api/endpoints/users/groups/create.ts b/packages/backend/src/server/api/endpoints/users/groups/create.ts
index 25e29de01c..9f6d8464d8 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/create.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/create.ts
@@ -1,9 +1,8 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { UserGroups, UserGroupJoinings } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { UserGroup } from '@/models/entities/user-group';
-import { UserGroupJoining } from '@/models/entities/user-group-joining';
+import define from '../../../define.js';
+import { UserGroups, UserGroupJoinings } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { UserGroup } from '@/models/entities/user-group.js';
+import { UserGroupJoining } from '@/models/entities/user-group-joining.js';
 
 export const meta = {
 	tags: ['groups'],
@@ -12,12 +11,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		name: {
-			validator: $.str.range(1, 100),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -25,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+	},
+	required: ['name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const userGroup = await UserGroups.insert({
 		id: genId(),
 		createdAt: new Date(),
diff --git a/packages/backend/src/server/api/endpoints/users/groups/delete.ts b/packages/backend/src/server/api/endpoints/users/groups/delete.ts
index f30ab78ca0..f4898a3c7c 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/delete.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserGroups } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserGroups } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchGroup: {
 			message: 'No such group.',
@@ -26,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['groupId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/invitations/accept.ts b/packages/backend/src/server/api/endpoints/users/groups/invitations/accept.ts
index 7061db538b..efbdf968f6 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/invitations/accept.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/invitations/accept.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../../define';
-import { ApiError } from '../../../../error';
-import { UserGroupJoinings, UserGroupInvitations } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { UserGroupJoining } from '@/models/entities/user-group-joining';
+import define from '../../../../define.js';
+import { ApiError } from '../../../../error.js';
+import { UserGroupJoinings, UserGroupInvitations } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { UserGroupJoining } from '@/models/entities/user-group-joining.js';
 
 export const meta = {
 	tags: ['groups', 'users'],
@@ -13,12 +11,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		invitationId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchInvitation: {
 			message: 'No such invitation.',
@@ -28,8 +20,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		invitationId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['invitationId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch the invitation
 	const invitation = await UserGroupInvitations.findOne({
 		id: ps.invitationId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/invitations/reject.ts b/packages/backend/src/server/api/endpoints/users/groups/invitations/reject.ts
index f5ca3dec8b..fe5d431eab 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/invitations/reject.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/invitations/reject.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../../define';
-import { ApiError } from '../../../../error';
-import { UserGroupInvitations } from '@/models/index';
+import define from '../../../../define.js';
+import { ApiError } from '../../../../error.js';
+import { UserGroupInvitations } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups', 'users'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		invitationId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchInvitation: {
 			message: 'No such invitation.',
@@ -26,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		invitationId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['invitationId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch the invitation
 	const invitation = await UserGroupInvitations.findOne({
 		id: ps.invitationId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/invite.ts b/packages/backend/src/server/api/endpoints/users/groups/invite.ts
index 3b7a4edb81..10bfb7eca1 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/invite.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/invite.ts
@@ -1,12 +1,10 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { UserGroups, UserGroupJoinings, UserGroupInvitations } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { UserGroupInvitation } from '@/models/entities/user-group-invitation';
-import { createNotification } from '@/services/create-notification';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { UserGroups, UserGroupJoinings, UserGroupInvitations } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { UserGroupInvitation } from '@/models/entities/user-group-invitation.js';
+import { createNotification } from '@/services/create-notification.js';
 
 export const meta = {
 	tags: ['groups', 'users'],
@@ -15,16 +13,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchGroup: {
 			message: 'No such group.',
@@ -52,8 +40,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['groupId', 'userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the group
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/joined.ts b/packages/backend/src/server/api/endpoints/users/groups/joined.ts
index ab48b1910d..e52de78595 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/joined.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/joined.ts
@@ -1,5 +1,5 @@
-import define from '../../../define';
-import { UserGroups, UserGroupJoinings } from '@/models/index';
+import define from '../../../define.js';
+import { UserGroups, UserGroupJoinings } from '@/models/index.js';
 import { Not, In } from 'typeorm';
 
 export const meta = {
@@ -20,8 +20,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const ownedGroups = await UserGroups.find({
 		userId: me.id,
 	});
diff --git a/packages/backend/src/server/api/endpoints/users/groups/leave.ts b/packages/backend/src/server/api/endpoints/users/groups/leave.ts
index d2fcdab301..c1a8c2c024 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/leave.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/leave.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserGroups, UserGroupJoinings } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserGroups, UserGroupJoinings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups', 'users'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchGroup: {
 			message: 'No such group.',
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['groupId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the group
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/owned.ts b/packages/backend/src/server/api/endpoints/users/groups/owned.ts
index 6193a71019..11aad0f73c 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/owned.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/owned.ts
@@ -1,5 +1,5 @@
-import define from '../../../define';
-import { UserGroups } from '@/models/index';
+import define from '../../../define.js';
+import { UserGroups } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups', 'account'],
@@ -19,8 +19,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const userGroups = await UserGroups.find({
 		userId: me.id,
 	});
diff --git a/packages/backend/src/server/api/endpoints/users/groups/pull.ts b/packages/backend/src/server/api/endpoints/users/groups/pull.ts
index 785bea140d..55ec9f915b 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/pull.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/pull.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { UserGroups, UserGroupJoinings } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { UserGroups, UserGroupJoinings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups', 'users'],
@@ -12,16 +10,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchGroup: {
 			message: 'No such group.',
@@ -43,8 +31,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['groupId', 'userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the group
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/show.ts b/packages/backend/src/server/api/endpoints/users/groups/show.ts
index eb26eac2a8..28ca1162c8 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/show.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/show.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserGroups, UserGroupJoinings } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserGroups, UserGroupJoinings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups', 'account'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'read:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['groupId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the group
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/transfer.ts b/packages/backend/src/server/api/endpoints/users/groups/transfer.ts
index 4b1c8fbbdb..f48e1ddbf0 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/transfer.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/transfer.ts
@@ -1,9 +1,7 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { UserGroups, UserGroupJoinings } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { UserGroups, UserGroupJoinings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups', 'users'],
@@ -12,16 +10,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -49,8 +37,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['groupId', 'userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the group
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
diff --git a/packages/backend/src/server/api/endpoints/users/groups/update.ts b/packages/backend/src/server/api/endpoints/users/groups/update.ts
index 6caf903555..b3e17dfd9e 100644
--- a/packages/backend/src/server/api/endpoints/users/groups/update.ts
+++ b/packages/backend/src/server/api/endpoints/users/groups/update.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserGroups } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserGroups } from '@/models/index.js';
 
 export const meta = {
 	tags: ['groups'],
@@ -11,16 +9,6 @@ export const meta = {
 
 	kind: 'write:user-groups',
 
-	params: {
-		groupId: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.str.range(1, 100),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -36,8 +24,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		groupId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+	},
+	required: ['groupId', 'name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the group
 	const userGroup = await UserGroups.findOne({
 		id: ps.groupId,
diff --git a/packages/backend/src/server/api/endpoints/users/lists/create.ts b/packages/backend/src/server/api/endpoints/users/lists/create.ts
index 945b511628..1a0599f9e7 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/create.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/create.ts
@@ -1,8 +1,7 @@
-import $ from 'cafy';
-import define from '../../../define';
-import { UserLists } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { UserList } from '@/models/entities/user-list';
+import define from '../../../define.js';
+import { UserLists } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { UserList } from '@/models/entities/user-list.js';
 
 export const meta = {
 	tags: ['lists'],
@@ -11,12 +10,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		name: {
-			validator: $.str.range(1, 100),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -24,8 +17,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+	},
+	required: ['name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const userList = await UserLists.insert({
 		id: genId(),
 		createdAt: new Date(),
diff --git a/packages/backend/src/server/api/endpoints/users/lists/delete.ts b/packages/backend/src/server/api/endpoints/users/lists/delete.ts
index 3183d2a09c..aeefb98c83 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/delete.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/delete.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserLists } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserLists } from '@/models/index.js';
 
 export const meta = {
 	tags: ['lists'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		listId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchList: {
 			message: 'No such list.',
@@ -26,8 +18,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		listId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['listId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const userList = await UserLists.findOne({
 		id: ps.listId,
 		userId: user.id,
diff --git a/packages/backend/src/server/api/endpoints/users/lists/list.ts b/packages/backend/src/server/api/endpoints/users/lists/list.ts
index ae66b0aacc..a8663ada8a 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/list.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/list.ts
@@ -1,5 +1,5 @@
-import define from '../../../define';
-import { UserLists } from '@/models/index';
+import define from '../../../define.js';
+import { UserLists } from '@/models/index.js';
 
 export const meta = {
 	tags: ['lists', 'account'],
@@ -19,8 +19,14 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const userLists = await UserLists.find({
 		userId: me.id,
 	});
diff --git a/packages/backend/src/server/api/endpoints/users/lists/pull.ts b/packages/backend/src/server/api/endpoints/users/lists/pull.ts
index 4c74aefa8a..2c4c61d51e 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/pull.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/pull.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import { publishUserListStream } from '@/services/stream';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { UserLists, UserListJoinings, Users } from '@/models/index';
+import { publishUserListStream } from '@/services/stream.js';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { UserLists, UserListJoinings, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['lists', 'users'],
@@ -13,16 +11,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		listId: {
-			validator: $.type(ID),
-		},
-
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchList: {
 			message: 'No such list.',
@@ -38,8 +26,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		listId: { type: 'string', format: 'misskey:id' },
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['listId', 'userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the list
 	const userList = await UserLists.findOne({
 		id: ps.listId,
diff --git a/packages/backend/src/server/api/endpoints/users/lists/push.ts b/packages/backend/src/server/api/endpoints/users/lists/push.ts
index 8b50c475b0..034a9d2db6 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/push.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/push.ts
@@ -1,10 +1,8 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { getUser } from '../../../common/getters';
-import { pushUserToUserList } from '@/services/user-list/push';
-import { UserLists, UserListJoinings, Blockings } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { getUser } from '../../../common/getters.js';
+import { pushUserToUserList } from '@/services/user-list/push.js';
+import { UserLists, UserListJoinings, Blockings } from '@/models/index.js';
 
 export const meta = {
 	tags: ['lists', 'users'],
@@ -13,16 +11,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		listId: {
-			validator: $.type(ID),
-		},
-
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchList: {
 			message: 'No such list.',
@@ -50,8 +38,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		listId: { type: 'string', format: 'misskey:id' },
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['listId', 'userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the list
 	const userList = await UserLists.findOne({
 		id: ps.listId,
diff --git a/packages/backend/src/server/api/endpoints/users/lists/show.ts b/packages/backend/src/server/api/endpoints/users/lists/show.ts
index 06555c1a88..fadb94c90e 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/show.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/show.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserLists } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserLists } from '@/models/index.js';
 
 export const meta = {
 	tags: ['lists', 'account'],
@@ -11,12 +9,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-		listId: {
-			validator: $.type(ID),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -32,8 +24,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		listId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['listId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Fetch the list
 	const userList = await UserLists.findOne({
 		id: ps.listId,
diff --git a/packages/backend/src/server/api/endpoints/users/lists/update.ts b/packages/backend/src/server/api/endpoints/users/lists/update.ts
index 02b0d5fe18..5ec99031e1 100644
--- a/packages/backend/src/server/api/endpoints/users/lists/update.ts
+++ b/packages/backend/src/server/api/endpoints/users/lists/update.ts
@@ -1,8 +1,6 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../../define';
-import { ApiError } from '../../../error';
-import { UserLists } from '@/models/index';
+import define from '../../../define.js';
+import { ApiError } from '../../../error.js';
+import { UserLists } from '@/models/index.js';
 
 export const meta = {
 	tags: ['lists'],
@@ -11,16 +9,6 @@ export const meta = {
 
 	kind: 'write:account',
 
-	params: {
-		listId: {
-			validator: $.type(ID),
-		},
-
-		name: {
-			validator: $.str.range(1, 100),
-		},
-	},
-
 	res: {
 		type: 'object',
 		optional: false, nullable: false,
@@ -36,8 +24,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		listId: { type: 'string', format: 'misskey:id' },
+		name: { type: 'string', minLength: 1, maxLength: 100 },
+	},
+	required: ['listId', 'name'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	// Fetch the list
 	const userList = await UserLists.findOne({
 		id: ps.listId,
diff --git a/packages/backend/src/server/api/endpoints/users/notes.ts b/packages/backend/src/server/api/endpoints/users/notes.ts
index 99158fb0ae..16318d2225 100644
--- a/packages/backend/src/server/api/endpoints/users/notes.ts
+++ b/packages/backend/src/server/api/endpoints/users/notes.ts
@@ -1,70 +1,17 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { Notes } from '@/models/index';
-import { generateMutedUserQuery } from '../../common/generate-muted-user-query';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { Notes } from '@/models/index.js';
+import { generateMutedUserQuery } from '../../common/generate-muted-user-query.js';
 import { Brackets } from 'typeorm';
-import { generateBlockedUserQuery } from '../../common/generate-block-query';
-import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query';
+import { generateBlockedUserQuery } from '../../common/generate-block-query.js';
+import { generateMutedInstanceQuery } from '../../common/generate-muted-instance-query.js';
 
 export const meta = {
 	tags: ['users', 'notes'],
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		includeReplies: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-
-		includeMyRenotes: {
-			validator: $.optional.bool,
-			default: true,
-		},
-
-		withFiles: {
-			validator: $.optional.bool,
-			default: false,
-		},
-
-		fileType: {
-			validator: $.optional.arr($.str),
-		},
-
-		excludeNsfw: {
-			validator: $.optional.bool,
-			default: false,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -84,8 +31,28 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		includeReplies: { type: 'boolean', default: true },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+		includeMyRenotes: { type: 'boolean', default: true },
+		withFiles: { type: 'boolean', default: false },
+		fileType: { type: 'array', items: {
+			type: 'string',
+		} },
+		excludeNsfw: { type: 'boolean', default: false },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Lookup user
 	const user = await getUser(ps.userId).catch(e => {
 		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
@@ -96,10 +63,16 @@ export default define(meta, async (ps, me) => {
 	const query = makePaginationQuery(Notes.createQueryBuilder('note'), ps.sinceId, ps.untilId, ps.sinceDate, ps.untilDate)
 		.andWhere('note.userId = :userId', { userId: user.id })
 		.innerJoinAndSelect('note.user', 'user')
+		.leftJoinAndSelect('user.avatar', 'avatar')
+		.leftJoinAndSelect('user.banner', 'banner')
 		.leftJoinAndSelect('note.reply', 'reply')
 		.leftJoinAndSelect('note.renote', 'renote')
 		.leftJoinAndSelect('reply.user', 'replyUser')
-		.leftJoinAndSelect('renote.user', 'renoteUser');
+		.leftJoinAndSelect('replyUser.avatar', 'replyUserAvatar')
+		.leftJoinAndSelect('replyUser.banner', 'replyUserBanner')
+		.leftJoinAndSelect('renote.user', 'renoteUser')
+		.leftJoinAndSelect('renoteUser.avatar', 'renoteUserAvatar')
+		.leftJoinAndSelect('renoteUser.banner', 'renoteUserBanner');
 
 	generateVisibilityQuery(query, me);
 	if (me) generateMutedUserQuery(query, me, user);
@@ -141,7 +114,7 @@ export default define(meta, async (ps, me) => {
 
 	//#endregion
 
-	const timeline = await query.take(ps.limit!).getMany();
+	const timeline = await query.take(ps.limit).getMany();
 
 	return await Notes.packMany(timeline, me);
 });
diff --git a/packages/backend/src/server/api/endpoints/users/pages.ts b/packages/backend/src/server/api/endpoints/users/pages.ts
index 6e003dd1af..b8b3e8192e 100644
--- a/packages/backend/src/server/api/endpoints/users/pages.ts
+++ b/packages/backend/src/server/api/endpoints/users/pages.ts
@@ -1,40 +1,30 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { Pages } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
+import define from '../../define.js';
+import { Pages } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
 
 export const meta = {
 	tags: ['users', 'pages'],
+} as const;
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
 	},
+	required: ['userId'],
 } as const;
 
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, user) => {
+export default define(meta, paramDef, async (ps, user) => {
 	const query = makePaginationQuery(Pages.createQueryBuilder('page'), ps.sinceId, ps.untilId)
 		.andWhere(`page.userId = :userId`, { userId: ps.userId })
 		.andWhere('page.visibility = \'public\'');
 
 	const pages = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Pages.packMany(pages);
diff --git a/packages/backend/src/server/api/endpoints/users/reactions.ts b/packages/backend/src/server/api/endpoints/users/reactions.ts
index 312d4dbf23..7b55a16711 100644
--- a/packages/backend/src/server/api/endpoints/users/reactions.ts
+++ b/packages/backend/src/server/api/endpoints/users/reactions.ts
@@ -1,43 +1,14 @@
-import $ from 'cafy';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { NoteReactions, UserProfiles } from '@/models/index';
-import { makePaginationQuery } from '../../common/make-pagination-query';
-import { generateVisibilityQuery } from '../../common/generate-visibility-query';
-import { ApiError } from '../../error';
+import define from '../../define.js';
+import { NoteReactions, UserProfiles } from '@/models/index.js';
+import { makePaginationQuery } from '../../common/make-pagination-query.js';
+import { generateVisibilityQuery } from '../../common/generate-visibility-query.js';
+import { ApiError } from '../../error.js';
 
 export const meta = {
 	tags: ['users', 'reactions'],
 
 	requireCredential: false,
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		sinceId: {
-			validator: $.optional.type(ID),
-		},
-
-		untilId: {
-			validator: $.optional.type(ID),
-		},
-
-		sinceDate: {
-			validator: $.optional.num,
-		},
-
-		untilDate: {
-			validator: $.optional.num,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -57,8 +28,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		sinceId: { type: 'string', format: 'misskey:id' },
+		untilId: { type: 'string', format: 'misskey:id' },
+		sinceDate: { type: 'integer' },
+		untilDate: { type: 'integer' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const profile = await UserProfiles.findOneOrFail(ps.userId);
 
 	if (me == null || (me.id !== ps.userId && !profile.publicReactions)) {
@@ -73,7 +57,7 @@ export default define(meta, async (ps, me) => {
 	generateVisibilityQuery(query, me);
 
 	const reactions = await query
-		.take(ps.limit!)
+		.take(ps.limit)
 		.getMany();
 
 	return await Promise.all(reactions.map(reaction => NoteReactions.pack(reaction, me, { withNote: true })));
diff --git a/packages/backend/src/server/api/endpoints/users/recommendation.ts b/packages/backend/src/server/api/endpoints/users/recommendation.ts
index 9ea39eb2dd..a8f18de522 100644
--- a/packages/backend/src/server/api/endpoints/users/recommendation.ts
+++ b/packages/backend/src/server/api/endpoints/users/recommendation.ts
@@ -1,9 +1,8 @@
 import ms from 'ms';
-import $ from 'cafy';
-import define from '../../define';
-import { Users, Followings } from '@/models/index';
-import { generateMutedUserQueryForUsers } from '../../common/generate-muted-user-query';
-import { generateBlockedUserQuery, generateBlockQueryForUsers } from '../../common/generate-block-query';
+import define from '../../define.js';
+import { Users, Followings } from '@/models/index.js';
+import { generateMutedUserQueryForUsers } from '../../common/generate-muted-user-query.js';
+import { generateBlockedUserQuery, generateBlockQueryForUsers } from '../../common/generate-block-query.js';
 
 export const meta = {
 	tags: ['users'],
@@ -12,18 +11,6 @@ export const meta = {
 
 	kind: 'read:account',
 
-	params: {
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -35,8 +22,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		offset: { type: 'integer', default: 0 },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const query = Users.createQueryBuilder('user')
 		.where('user.isLocked = FALSE')
 		.andWhere('user.isExplorable = TRUE')
@@ -58,7 +54,7 @@ export default define(meta, async (ps, me) => {
 
 	query.setParameters(followingQuery.getParameters());
 
-	const users = await query.take(ps.limit!).skip(ps.offset).getMany();
+	const users = await query.take(ps.limit).skip(ps.offset).getMany();
 
 	return await Users.packMany(users, me, { detail: true });
 });
diff --git a/packages/backend/src/server/api/endpoints/users/relation.ts b/packages/backend/src/server/api/endpoints/users/relation.ts
index 7e319ca105..c6262122d4 100644
--- a/packages/backend/src/server/api/endpoints/users/relation.ts
+++ b/packages/backend/src/server/api/endpoints/users/relation.ts
@@ -1,19 +1,11 @@
-import $ from 'cafy';
-import define from '../../define';
-import { ID } from '@/misc/cafy-id';
-import { Users } from '@/models/index';
+import define from '../../define.js';
+import { Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: true,
 
-	params: {
-		userId: {
-			validator: $.either($.type(ID), $.arr($.type(ID)).unique()),
-		},
-	},
-
 	res: {
 		optional: false, nullable: false,
 		oneOf: [
@@ -101,8 +93,24 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: {
+			anyOf: [
+				{ type: 'string', format: 'misskey:id' },
+				{
+					type: 'array',
+					items: { type: 'string', format: 'misskey:id' },
+				},
+			],
+		},
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const ids = Array.isArray(ps.userId) ? ps.userId : [ps.userId];
 
 	const relations = await Promise.all(ids.map(id => Users.getRelation(me.id, id)));
diff --git a/packages/backend/src/server/api/endpoints/users/report-abuse.ts b/packages/backend/src/server/api/endpoints/users/report-abuse.ts
index ed2aa7bb26..e091b8e1b1 100644
--- a/packages/backend/src/server/api/endpoints/users/report-abuse.ts
+++ b/packages/backend/src/server/api/endpoints/users/report-abuse.ts
@@ -1,30 +1,18 @@
-import $ from 'cafy';
 import * as sanitizeHtml from 'sanitize-html';
-import { ID } from '@/misc/cafy-id';
-import define from '../../define';
-import { publishAdminStream } from '@/services/stream';
-import { ApiError } from '../../error';
-import { getUser } from '../../common/getters';
-import { AbuseUserReports, Users } from '@/models/index';
-import { genId } from '@/misc/gen-id';
-import { sendEmail } from '@/services/send-email';
-import { fetchMeta } from '@/misc/fetch-meta';
+import define from '../../define.js';
+import { publishAdminStream } from '@/services/stream.js';
+import { ApiError } from '../../error.js';
+import { getUser } from '../../common/getters.js';
+import { AbuseUserReports, Users } from '@/models/index.js';
+import { genId } from '@/misc/gen-id.js';
+import { sendEmail } from '@/services/send-email.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: true,
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-
-		comment: {
-			validator: $.str.range(1, 2048),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -46,8 +34,17 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		comment: { type: 'string', minLength: 1, maxLength: 2048 },
+	},
+	required: ['userId', 'comment'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	// Lookup user
 	const user = await getUser(ps.userId).catch(e => {
 		if (e.id === '15348ddd-432d-49c2-8a5a-8069753becff') throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts b/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts
index 72e79c8824..897b5de3fe 100644
--- a/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts
+++ b/packages/backend/src/server/api/endpoints/users/search-by-username-and-host.ts
@@ -1,35 +1,14 @@
-import $ from 'cafy';
-import define from '../../define';
-import { Followings, Users } from '@/models/index';
+import define from '../../define.js';
+import { Followings, Users } from '@/models/index.js';
 import { Brackets } from 'typeorm';
-import { USER_ACTIVE_THRESHOLD } from '@/const';
-import { User } from '@/models/entities/user';
+import { USER_ACTIVE_THRESHOLD } from '@/const.js';
+import { User } from '@/models/entities/user.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		username: {
-			validator: $.optional.nullable.str,
-		},
-
-		host: {
-			validator: $.optional.nullable.str,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		detail: {
-			validator: $.optional.bool,
-			default: true,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -41,8 +20,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		username: { type: 'string', nullable: true },
+		host: { type: 'string', nullable: true },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		detail: { type: 'boolean', default: true },
+	},
+	required: [],
+} as const;
+
+// TODO: avatar,bannerをJOINしたいけどエラーになる
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const activeThreshold = new Date(Date.now() - (1000 * 60 * 60 * 24 * 30)); // 30日
 
 	if (ps.host) {
@@ -57,7 +49,7 @@ export default define(meta, async (ps, me) => {
 		q.andWhere('user.updatedAt IS NOT NULL');
 		q.orderBy('user.updatedAt', 'DESC');
 
-		const users = await q.take(ps.limit!).getMany();
+		const users = await q.take(ps.limit).getMany();
 
 		return await Users.packMany(users, me, { detail: ps.detail });
 	} else if (ps.username) {
@@ -82,10 +74,10 @@ export default define(meta, async (ps, me) => {
 
 			users = await query
 				.orderBy('user.usernameLower', 'ASC')
-				.take(ps.limit!)
+				.take(ps.limit)
 				.getMany();
 
-			if (users.length < ps.limit!) {
+			if (users.length < ps.limit) {
 				const otherQuery = await Users.createQueryBuilder('user')
 					.where(`user.id NOT IN (${ followingQuery.getQuery() })`)
 					.andWhere(`user.id != :meId`, { meId: me.id })
@@ -97,7 +89,7 @@ export default define(meta, async (ps, me) => {
 
 				const otherUsers = await otherQuery
 					.orderBy('user.updatedAt', 'DESC')
-					.take(ps.limit! - users.length)
+					.take(ps.limit - users.length)
 					.getMany();
 
 				users = users.concat(otherUsers);
@@ -108,7 +100,7 @@ export default define(meta, async (ps, me) => {
 				.andWhere('user.usernameLower LIKE :username', { username: ps.username.toLowerCase() + '%' })
 				.andWhere('user.updatedAt IS NOT NULL')
 				.orderBy('user.updatedAt', 'DESC')
-				.take(ps.limit! - users.length)
+				.take(ps.limit - users.length)
 				.getMany();
 		}
 
diff --git a/packages/backend/src/server/api/endpoints/users/search.ts b/packages/backend/src/server/api/endpoints/users/search.ts
index 26f818afcc..a72a58a843 100644
--- a/packages/backend/src/server/api/endpoints/users/search.ts
+++ b/packages/backend/src/server/api/endpoints/users/search.ts
@@ -1,7 +1,6 @@
-import $ from 'cafy';
-import define from '../../define';
-import { UserProfiles, Users } from '@/models/index';
-import { User } from '@/models/entities/user';
+import define from '../../define.js';
+import { UserProfiles, Users } from '@/models/index.js';
+import { User } from '@/models/entities/user.js';
 import { Brackets } from 'typeorm';
 
 export const meta = {
@@ -9,32 +8,6 @@ export const meta = {
 
 	requireCredential: false,
 
-	params: {
-		query: {
-			validator: $.str,
-		},
-
-		offset: {
-			validator: $.optional.num.min(0),
-			default: 0,
-		},
-
-		limit: {
-			validator: $.optional.num.range(1, 100),
-			default: 10,
-		},
-
-		origin: {
-			validator: $.optional.str.or(['local', 'remote', 'combined']),
-			default: 'combined',
-		},
-
-		detail: {
-			validator: $.optional.bool,
-			default: true,
-		},
-	},
-
 	res: {
 		type: 'array',
 		optional: false, nullable: false,
@@ -46,8 +19,20 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		query: { type: 'string' },
+		offset: { type: 'integer', default: 0 },
+		limit: { type: 'integer', minimum: 1, maximum: 100, default: 10 },
+		origin: { type: 'string', enum: ['local', 'remote', 'combined'], default: "combined" },
+		detail: { type: 'boolean', default: true },
+	},
+	required: ['query'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const activeThreshold = new Date(Date.now() - (1000 * 60 * 60 * 24 * 30)); // 30日
 
 	const isUsername = ps.query.startsWith('@');
@@ -71,7 +56,7 @@ export default define(meta, async (ps, me) => {
 
 		users = await usernameQuery
 			.orderBy('user.updatedAt', 'DESC', 'NULLS LAST')
-			.take(ps.limit!)
+			.take(ps.limit)
 			.skip(ps.offset)
 			.getMany();
 	} else {
@@ -91,11 +76,11 @@ export default define(meta, async (ps, me) => {
 
 		users = await nameQuery
 			.orderBy('user.updatedAt', 'DESC', 'NULLS LAST')
-			.take(ps.limit!)
+			.take(ps.limit)
 			.skip(ps.offset)
 			.getMany();
 
-		if (users.length < ps.limit!) {
+		if (users.length < ps.limit) {
 			const profQuery = UserProfiles.createQueryBuilder('prof')
 				.select('prof.userId')
 				.where('prof.description ILIKE :query', { query: '%' + ps.query + '%' });
@@ -117,7 +102,7 @@ export default define(meta, async (ps, me) => {
 
 			users = users.concat(await query
 				.orderBy('user.updatedAt', 'DESC', 'NULLS LAST')
-				.take(ps.limit!)
+				.take(ps.limit)
 				.skip(ps.offset)
 				.getMany()
 			);
diff --git a/packages/backend/src/server/api/endpoints/users/show.ts b/packages/backend/src/server/api/endpoints/users/show.ts
index 92910e9ed8..263c102a7a 100644
--- a/packages/backend/src/server/api/endpoints/users/show.ts
+++ b/packages/backend/src/server/api/endpoints/users/show.ts
@@ -1,36 +1,16 @@
-import $ from 'cafy';
-import { resolveUser } from '@/remote/resolve-user';
-import define from '../../define';
-import { apiLogger } from '../../logger';
-import { ApiError } from '../../error';
-import { ID } from '@/misc/cafy-id';
-import { Users } from '@/models/index';
+import { resolveUser } from '@/remote/resolve-user.js';
+import define from '../../define.js';
+import { apiLogger } from '../../logger.js';
+import { ApiError } from '../../error.js';
+import { Users } from '@/models/index.js';
 import { In } from 'typeorm';
-import { User } from '@/models/entities/user';
+import { User } from '@/models/entities/user.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		userId: {
-			validator: $.optional.type(ID),
-		},
-
-		userIds: {
-			validator: $.optional.arr($.type(ID)).unique(),
-		},
-
-		username: {
-			validator: $.optional.str,
-		},
-
-		host: {
-			validator: $.optional.nullable.str,
-		},
-	},
-
 	res: {
 		optional: false, nullable: false,
 		oneOf: [
@@ -64,8 +44,21 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+		userIds: { type: 'array', uniqueItems: true, items: {
+			type: 'string', format: 'misskey:id',
+		} },
+		username: { type: 'string' },
+		host: { type: 'string', nullable: true },
+	},
+	required: [],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	let user;
 
 	const isAdminOrModerator = me && (me.isAdmin || me.isModerator);
diff --git a/packages/backend/src/server/api/endpoints/users/stats.ts b/packages/backend/src/server/api/endpoints/users/stats.ts
index 381e433479..180a9386d3 100644
--- a/packages/backend/src/server/api/endpoints/users/stats.ts
+++ b/packages/backend/src/server/api/endpoints/users/stats.ts
@@ -1,20 +1,12 @@
-import $ from 'cafy';
-import define from '../../define';
-import { ApiError } from '../../error';
-import { ID } from '@/misc/cafy-id';
-import { DriveFiles, Followings, NoteFavorites, NoteReactions, Notes, PageLikes, PollVotes, Users } from '@/models/index';
+import define from '../../define.js';
+import { ApiError } from '../../error.js';
+import { DriveFiles, Followings, NoteFavorites, NoteReactions, Notes, PageLikes, PollVotes, Users } from '@/models/index.js';
 
 export const meta = {
 	tags: ['users'],
 
 	requireCredential: false,
 
-	params: {
-		userId: {
-			validator: $.type(ID),
-		},
-	},
-
 	errors: {
 		noSuchUser: {
 			message: 'No such user.',
@@ -24,8 +16,16 @@ export const meta = {
 	},
 } as const;
 
+export const paramDef = {
+	type: 'object',
+	properties: {
+		userId: { type: 'string', format: 'misskey:id' },
+	},
+	required: ['userId'],
+} as const;
+
 // eslint-disable-next-line import/no-default-export
-export default define(meta, async (ps, me) => {
+export default define(meta, paramDef, async (ps, me) => {
 	const user = await Users.findOne(ps.userId);
 	if (user == null) {
 		throw new ApiError(meta.errors.noSuchUser);
diff --git a/packages/backend/src/server/api/index.ts b/packages/backend/src/server/api/index.ts
index 8f8a9d999e..ba2a71951c 100644
--- a/packages/backend/src/server/api/index.ts
+++ b/packages/backend/src/server/api/index.ts
@@ -2,22 +2,22 @@
  * API Server
  */
 
-import * as Koa from 'koa';
-import * as Router from '@koa/router';
-import * as multer from '@koa/multer';
-import * as bodyParser from 'koa-bodyparser';
-import * as cors from '@koa/cors';
+import Koa from 'koa';
+import Router from '@koa/router';
+import multer from '@koa/multer';
+import bodyParser from 'koa-bodyparser';
+import cors from '@koa/cors';
 
-import endpoints from './endpoints';
-import handler from './api-handler';
-import signup from './private/signup';
-import signin from './private/signin';
-import signupPending from './private/signup-pending';
-import discord from './service/discord';
-import github from './service/github';
-import twitter from './service/twitter';
-import { Instances, AccessTokens, Users } from '@/models/index';
-import config from '@/config';
+import endpoints from './endpoints.js';
+import handler from './api-handler.js';
+import signup from './private/signup.js';
+import signin from './private/signin.js';
+import signupPending from './private/signup-pending.js';
+import discord from './service/discord.js';
+import github from './service/github.js';
+import twitter from './service/twitter.js';
+import { Instances, AccessTokens, Users } from '@/models/index.js';
+import config from '@/config/index.js';
 
 // Init app
 const app = new Koa();
diff --git a/packages/backend/src/server/api/limiter.ts b/packages/backend/src/server/api/limiter.ts
index 4721f6263a..7e6b93b39f 100644
--- a/packages/backend/src/server/api/limiter.ts
+++ b/packages/backend/src/server/api/limiter.ts
@@ -1,9 +1,9 @@
-import * as Limiter from 'ratelimiter';
-import { redisClient } from '../../db/redis';
-import { IEndpoint } from './endpoints';
-import * as Acct from 'misskey-js/built/acct';
-import { User } from '@/models/entities/user';
-import Logger from '@/services/logger';
+import Limiter from 'ratelimiter';
+import { redisClient } from '../../db/redis.js';
+import { IEndpoint } from './endpoints.js';
+import * as Acct from '@/misc/acct.js';
+import { User } from '@/models/entities/user.js';
+import Logger from '@/services/logger.js';
 
 const logger = new Logger('limiter');
 
diff --git a/packages/backend/src/server/api/logger.ts b/packages/backend/src/server/api/logger.ts
index 750defe547..ec22d6c3e2 100644
--- a/packages/backend/src/server/api/logger.ts
+++ b/packages/backend/src/server/api/logger.ts
@@ -1,3 +1,3 @@
-import Logger from '@/services/logger';
+import Logger from '@/services/logger.js';
 
 export const apiLogger = new Logger('api');
diff --git a/packages/backend/src/server/api/openapi/gen-spec.ts b/packages/backend/src/server/api/openapi/gen-spec.ts
index 1efef8d26d..c6e557aefb 100644
--- a/packages/backend/src/server/api/openapi/gen-spec.ts
+++ b/packages/backend/src/server/api/openapi/gen-spec.ts
@@ -1,8 +1,7 @@
-import endpoints from '../endpoints';
-import { Context } from 'cafy';
-import config from '@/config/index';
-import { errors as basicErrors } from './errors';
-import { schemas, convertSchemaToOpenApiSchema } from './schemas';
+import endpoints from '../endpoints.js';
+import config from '@/config/index.js';
+import { errors as basicErrors } from './errors.js';
+import { schemas, convertSchemaToOpenApiSchema } from './schemas.js';
 
 export function genOpenapiSpec(lang = 'ja-JP') {
 	const spec = {
@@ -38,47 +37,7 @@ export function genOpenapiSpec(lang = 'ja-JP') {
 		},
 	};
 
-	function genProps(props: { [key: string]: Context; }) {
-		const properties = {} as any;
-
-		for (const [k, v] of Object.entries(props)) {
-			properties[k] = genProp(v);
-		}
-
-		return properties;
-	}
-
-	function genProp(param: Context): any {
-		const required = param.name === 'Object' ? (param as any).props ? Object.entries((param as any).props).filter(([k, v]: any) => !v.isOptional).map(([k, v]) => k) : [] : [];
-		return {
-			description: (param.data || {}).desc,
-			default: (param.data || {}).default,
-			deprecated: (param.data || {}).deprecated,
-			...((param.data || {}).default ? { default: (param.data || {}).default } : {}),
-			type: param.name === 'ID' ? 'string' : param.name.toLowerCase(),
-			...(param.name === 'ID' ? { example: 'xxxxxxxxxx', format: 'id' } : {}),
-			nullable: param.isNullable,
-			...(param.name === 'String' ? {
-				...((param as any).enum ? { enum: (param as any).enum } : {}),
-				...((param as any).minLength ? { minLength: (param as any).minLength } : {}),
-				...((param as any).maxLength ? { maxLength: (param as any).maxLength } : {}),
-			} : {}),
-			...(param.name === 'Number' ? {
-				...((param as any).minimum ? { minimum: (param as any).minimum } : {}),
-				...((param as any).maximum ? { maximum: (param as any).maximum } : {}),
-			} : {}),
-			...(param.name === 'Object' ? {
-				...(required.length > 0 ? { required } : {}),
-				properties: (param as any).props ? genProps((param as any).props) : {},
-			} : {}),
-			...(param.name === 'Array' ? {
-				items: (param as any).ctx ? genProp((param as any).ctx) : {},
-			} : {}),
-		};
-	}
-
 	for (const endpoint of endpoints.filter(ep => !ep.meta.secure)) {
-		const porops = {} as any;
 		const errors = {} as any;
 
 		if (endpoint.meta.errors) {
@@ -91,21 +50,9 @@ export function genOpenapiSpec(lang = 'ja-JP') {
 			}
 		}
 
-		if (endpoint.meta.params) {
-			for (const [k, v] of Object.entries(endpoint.meta.params)) {
-				if (v.validator.data == null) v.validator.data = {};
-				if (v.desc) v.validator.data.desc = v.desc[lang];
-				if (v.deprecated) v.validator.data.deprecated = v.deprecated;
-				if (v.default) v.validator.data.default = v.default;
-				porops[k] = v.validator;
-			}
-		}
-
-		const required = endpoint.meta.params ? Object.entries(endpoint.meta.params).filter(([k, v]) => !v.validator.isOptional).map(([k, v]) => k) : [];
-
 		const resSchema = endpoint.meta.res ? convertSchemaToOpenApiSchema(endpoint.meta.res) : {};
 
-		let desc = (endpoint.meta.desc ? endpoint.meta.desc[lang] : 'No description provided.') + '\n\n';
+		let desc = (endpoint.meta.description ? endpoint.meta.description : 'No description provided.') + '\n\n';
 		desc += `**Credential required**: *${endpoint.meta.requireCredential ? 'Yes' : 'No'}*`;
 		if (endpoint.meta.kind) {
 			const kind = endpoint.meta.kind;
@@ -132,11 +79,7 @@ export function genOpenapiSpec(lang = 'ja-JP') {
 				required: true,
 				content: {
 					'application/json': {
-						schema: {
-							type: 'object',
-							...(required.length > 0 ? { required } : {}),
-							properties: endpoint.meta.params ? genProps(porops) : {},
-						},
+						schema: endpoint.params,
 					},
 				},
 			},
diff --git a/packages/backend/src/server/api/openapi/schemas.ts b/packages/backend/src/server/api/openapi/schemas.ts
index eb42667fd5..14bef9cab1 100644
--- a/packages/backend/src/server/api/openapi/schemas.ts
+++ b/packages/backend/src/server/api/openapi/schemas.ts
@@ -1,6 +1,6 @@
-import { refs, MinimumSchema } from '@/misc/schema';
+import { refs, Schema } from '@/misc/schema.js';
 
-export function convertSchemaToOpenApiSchema(schema: MinimumSchema) {
+export function convertSchemaToOpenApiSchema(schema: Schema) {
 	const res: any = schema;
 
 	if (schema.type === 'object' && schema.properties) {
diff --git a/packages/backend/src/server/api/private/signin.ts b/packages/backend/src/server/api/private/signin.ts
index 7b733b768d..b0f88948a0 100644
--- a/packages/backend/src/server/api/private/signin.ts
+++ b/packages/backend/src/server/api/private/signin.ts
@@ -1,13 +1,13 @@
-import * as Koa from 'koa';
-import * as bcrypt from 'bcryptjs';
+import Koa from 'koa';
+import bcrypt from 'bcryptjs';
 import * as speakeasy from 'speakeasy';
-import signin from '../common/signin';
-import config from '@/config/index';
-import { Users, Signins, UserProfiles, UserSecurityKeys, AttestationChallenges } from '@/models/index';
-import { ILocalUser } from '@/models/entities/user';
-import { genId } from '@/misc/gen-id';
-import { verifyLogin, hash } from '../2fa';
-import { randomBytes } from 'crypto';
+import signin from '../common/signin.js';
+import config from '@/config/index.js';
+import { Users, Signins, UserProfiles, UserSecurityKeys, AttestationChallenges } from '@/models/index.js';
+import { ILocalUser } from '@/models/entities/user.js';
+import { genId } from '@/misc/gen-id.js';
+import { verifyLogin, hash } from '../2fa.js';
+import { randomBytes } from 'node:crypto';
 
 export default async (ctx: Koa.Context) => {
 	ctx.set('Access-Control-Allow-Origin', config.url);
diff --git a/packages/backend/src/server/api/private/signup-pending.ts b/packages/backend/src/server/api/private/signup-pending.ts
index c0638a1cda..1a667ddb43 100644
--- a/packages/backend/src/server/api/private/signup-pending.ts
+++ b/packages/backend/src/server/api/private/signup-pending.ts
@@ -1,7 +1,7 @@
-import * as Koa from 'koa';
-import { Users, UserPendings, UserProfiles } from '@/models/index';
-import { signup } from '../common/signup';
-import signin from '../common/signin';
+import Koa from 'koa';
+import { Users, UserPendings, UserProfiles } from '@/models/index.js';
+import { signup } from '../common/signup.js';
+import signin from '../common/signin.js';
 
 export default async (ctx: Koa.Context) => {
 	const body = ctx.request.body;
diff --git a/packages/backend/src/server/api/private/signup.ts b/packages/backend/src/server/api/private/signup.ts
index eaab8e7111..01f284a57f 100644
--- a/packages/backend/src/server/api/private/signup.ts
+++ b/packages/backend/src/server/api/private/signup.ts
@@ -1,14 +1,14 @@
-import * as Koa from 'koa';
+import Koa from 'koa';
 import rndstr from 'rndstr';
-import * as bcrypt from 'bcryptjs';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { verifyHcaptcha, verifyRecaptcha } from '@/misc/captcha';
-import { Users, RegistrationTickets, UserPendings } from '@/models/index';
-import { signup } from '../common/signup';
-import config from '@/config';
-import { sendEmail } from '@/services/send-email';
-import { genId } from '@/misc/gen-id';
-import { validateEmailForAccount } from '@/services/validate-email-for-account';
+import bcrypt from 'bcryptjs';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { verifyHcaptcha, verifyRecaptcha } from '@/misc/captcha.js';
+import { Users, RegistrationTickets, UserPendings } from '@/models/index.js';
+import { signup } from '../common/signup.js';
+import config from '@/config/index.js';
+import { sendEmail } from '@/services/send-email.js';
+import { genId } from '@/misc/gen-id.js';
+import { validateEmailForAccount } from '@/services/validate-email-for-account.js';
 
 export default async (ctx: Koa.Context) => {
 	const body = ctx.request.body;
@@ -38,7 +38,7 @@ export default async (ctx: Koa.Context) => {
 	const emailAddress = body['emailAddress'];
 
 	if (instance.emailRequiredForSignup) {
-		if (emailAddress == null || typeof emailAddress != 'string') {
+		if (emailAddress == null || typeof emailAddress !== 'string') {
 			ctx.status = 400;
 			return;
 		}
@@ -51,7 +51,7 @@ export default async (ctx: Koa.Context) => {
 	}
 
 	if (instance.disableRegistration) {
-		if (invitationCode == null || typeof invitationCode != 'string') {
+		if (invitationCode == null || typeof invitationCode !== 'string') {
 			ctx.status = 400;
 			return;
 		}
diff --git a/packages/backend/src/server/api/service/discord.ts b/packages/backend/src/server/api/service/discord.ts
index dd731c422e..089f7de0cd 100644
--- a/packages/backend/src/server/api/service/discord.ts
+++ b/packages/backend/src/server/api/service/discord.ts
@@ -1,15 +1,15 @@
-import * as Koa from 'koa';
-import * as Router from '@koa/router';
-import { getJson } from '@/misc/fetch';
+import Koa from 'koa';
+import Router from '@koa/router';
+import { getJson } from '@/misc/fetch.js';
 import { OAuth2 } from 'oauth';
-import config from '@/config/index';
-import { publishMainStream } from '@/services/stream';
-import { redisClient } from '../../../db/redis';
+import config from '@/config/index.js';
+import { publishMainStream } from '@/services/stream.js';
+import { redisClient } from '../../../db/redis.js';
 import { v4 as uuid } from 'uuid';
-import signin from '../common/signin';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Users, UserProfiles } from '@/models/index';
-import { ILocalUser } from '@/models/entities/user';
+import signin from '../common/signin.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Users, UserProfiles } from '@/models/index.js';
+import { ILocalUser } from '@/models/entities/user.js';
 
 function getUserToken(ctx: Koa.BaseContext): string | null {
 	return ((ctx.headers['cookie'] || '').match(/igi=(\w+)/) || [null, null])[1];
diff --git a/packages/backend/src/server/api/service/github.ts b/packages/backend/src/server/api/service/github.ts
index b23219986a..ce032db181 100644
--- a/packages/backend/src/server/api/service/github.ts
+++ b/packages/backend/src/server/api/service/github.ts
@@ -1,15 +1,15 @@
-import * as Koa from 'koa';
-import * as Router from '@koa/router';
-import { getJson } from '@/misc/fetch';
+import Koa from 'koa';
+import Router from '@koa/router';
+import { getJson } from '@/misc/fetch.js';
 import { OAuth2 } from 'oauth';
-import config from '@/config/index';
-import { publishMainStream } from '@/services/stream';
-import { redisClient } from '../../../db/redis';
+import config from '@/config/index.js';
+import { publishMainStream } from '@/services/stream.js';
+import { redisClient } from '../../../db/redis.js';
 import { v4 as uuid } from 'uuid';
-import signin from '../common/signin';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Users, UserProfiles } from '@/models/index';
-import { ILocalUser } from '@/models/entities/user';
+import signin from '../common/signin.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Users, UserProfiles } from '@/models/index.js';
+import { ILocalUser } from '@/models/entities/user.js';
 
 function getUserToken(ctx: Koa.BaseContext): string | null {
 	return ((ctx.headers['cookie'] || '').match(/igi=(\w+)/) || [null, null])[1];
diff --git a/packages/backend/src/server/api/service/twitter.ts b/packages/backend/src/server/api/service/twitter.ts
index bca00b7924..e6e4398fa2 100644
--- a/packages/backend/src/server/api/service/twitter.ts
+++ b/packages/backend/src/server/api/service/twitter.ts
@@ -1,14 +1,14 @@
-import * as Koa from 'koa';
-import * as Router from '@koa/router';
+import Koa from 'koa';
+import Router from '@koa/router';
 import { v4 as uuid } from 'uuid';
 import autwh from 'autwh';
-import { redisClient } from '../../../db/redis';
-import { publishMainStream } from '@/services/stream';
-import config from '@/config/index';
-import signin from '../common/signin';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Users, UserProfiles } from '@/models/index';
-import { ILocalUser } from '@/models/entities/user';
+import { redisClient } from '../../../db/redis.js';
+import { publishMainStream } from '@/services/stream.js';
+import config from '@/config/index.js';
+import signin from '../common/signin.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Users, UserProfiles } from '@/models/index.js';
+import { ILocalUser } from '@/models/entities/user.js';
 
 function getUserToken(ctx: Koa.BaseContext): string | null {
 	return ((ctx.headers['cookie'] || '').match(/igi=(\w+)/) || [null, null])[1];
diff --git a/packages/backend/src/server/api/stream/channel.ts b/packages/backend/src/server/api/stream/channel.ts
index 98337bb318..d2cc5122d5 100644
--- a/packages/backend/src/server/api/stream/channel.ts
+++ b/packages/backend/src/server/api/stream/channel.ts
@@ -1,4 +1,3 @@
-import autobind from 'autobind-decorator';
 import Connection from '.';
 
 /**
@@ -44,7 +43,6 @@ export default abstract class Channel {
 		this.connection = connection;
 	}
 
-	@autobind
 	public send(typeOrPayload: any, payload?: any) {
 		const type = payload === undefined ? typeOrPayload.type : typeOrPayload;
 		const body = payload === undefined ? typeOrPayload.body : payload;
diff --git a/packages/backend/src/server/api/stream/channels/admin.ts b/packages/backend/src/server/api/stream/channels/admin.ts
index 1ff932d1dd..945182ea10 100644
--- a/packages/backend/src/server/api/stream/channels/admin.ts
+++ b/packages/backend/src/server/api/stream/channels/admin.ts
@@ -1,12 +1,10 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
+import Channel from '../channel.js';
 
 export default class extends Channel {
 	public readonly chName = 'admin';
 	public static shouldShare = true;
 	public static requireCredential = true;
 
-	@autobind
 	public async init(params: any) {
 		// Subscribe admin stream
 		this.subscriber.on(`adminStream:${this.user!.id}`, data => {
diff --git a/packages/backend/src/server/api/stream/channels/antenna.ts b/packages/backend/src/server/api/stream/channels/antenna.ts
index 3cbdfebb43..afd14946e1 100644
--- a/packages/backend/src/server/api/stream/channels/antenna.ts
+++ b/packages/backend/src/server/api/stream/channels/antenna.ts
@@ -1,9 +1,8 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
-import { Notes } from '@/models/index';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { StreamMessages } from '../types';
+import Channel from '../channel.js';
+import { Notes } from '@/models/index.js';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { StreamMessages } from '../types.js';
 
 export default class extends Channel {
 	public readonly chName = 'antenna';
@@ -11,7 +10,11 @@ export default class extends Channel {
 	public static requireCredential = false;
 	private antennaId: string;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onEvent = this.onEvent.bind(this);
+	}
+
 	public async init(params: any) {
 		this.antennaId = params.antennaId as string;
 
@@ -19,7 +22,6 @@ export default class extends Channel {
 		this.subscriber.on(`antennaStream:${this.antennaId}`, this.onEvent);
 	}
 
-	@autobind
 	private async onEvent(data: StreamMessages['antenna']['payload']) {
 		if (data.type === 'note') {
 			const note = await Notes.pack(data.body.id, this.user, { detail: true });
@@ -37,7 +39,6 @@ export default class extends Channel {
 		}
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off(`antennaStream:${this.antennaId}`, this.onEvent);
diff --git a/packages/backend/src/server/api/stream/channels/channel.ts b/packages/backend/src/server/api/stream/channels/channel.ts
index 1e51a81c4b..16ad809395 100644
--- a/packages/backend/src/server/api/stream/channels/channel.ts
+++ b/packages/backend/src/server/api/stream/channels/channel.ts
@@ -1,11 +1,10 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
-import { Notes, Users } from '@/models/index';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { User } from '@/models/entities/user';
-import { StreamMessages } from '../types';
-import { Packed } from '@/misc/schema';
+import Channel from '../channel.js';
+import { Notes, Users } from '@/models/index.js';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { User } from '@/models/entities/user.js';
+import { StreamMessages } from '../types.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'channel';
@@ -15,7 +14,11 @@ export default class extends Channel {
 	private typers: Record<User['id'], Date> = {};
 	private emitTypersIntervalId: ReturnType<typeof setInterval>;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		this.channelId = params.channelId as string;
 
@@ -25,7 +28,6 @@ export default class extends Channel {
 		this.emitTypersIntervalId = setInterval(this.emitTypers, 5000);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		if (note.channelId !== this.channelId) return;
 
@@ -52,7 +54,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	private onEvent(data: StreamMessages['channel']['payload']) {
 		if (data.type === 'typing') {
 			const id = data.body;
@@ -64,7 +65,6 @@ export default class extends Channel {
 		}
 	}
 
-	@autobind
 	private async emitTypers() {
 		const now = new Date();
 
@@ -81,7 +81,6 @@ export default class extends Channel {
 		});
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off('notesStream', this.onNote);
diff --git a/packages/backend/src/server/api/stream/channels/drive.ts b/packages/backend/src/server/api/stream/channels/drive.ts
index 4112dd9b04..140255acd1 100644
--- a/packages/backend/src/server/api/stream/channels/drive.ts
+++ b/packages/backend/src/server/api/stream/channels/drive.ts
@@ -1,12 +1,10 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
+import Channel from '../channel.js';
 
 export default class extends Channel {
 	public readonly chName = 'drive';
 	public static shouldShare = true;
 	public static requireCredential = true;
 
-	@autobind
 	public async init(params: any) {
 		// Subscribe drive stream
 		this.subscriber.on(`driveStream:${this.user!.id}`, data => {
diff --git a/packages/backend/src/server/api/stream/channels/global-timeline.ts b/packages/backend/src/server/api/stream/channels/global-timeline.ts
index ecd87d093d..1c7e038ab2 100644
--- a/packages/backend/src/server/api/stream/channels/global-timeline.ts
+++ b/packages/backend/src/server/api/stream/channels/global-timeline.ts
@@ -1,19 +1,22 @@
-import autobind from 'autobind-decorator';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import Channel from '../channel';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Notes } from '@/models/index';
-import { checkWordMute } from '@/misc/check-word-mute';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { isInstanceMuted } from '@/misc/is-instance-muted';
-import { Packed } from '@/misc/schema';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import Channel from '../channel.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Notes } from '@/models/index.js';
+import { checkWordMute } from '@/misc/check-word-mute.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { isInstanceMuted } from '@/misc/is-instance-muted.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'globalTimeline';
 	public static shouldShare = true;
 	public static requireCredential = false;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		const meta = await fetchMeta();
 		if (meta.disableGlobalTimeline) {
@@ -24,7 +27,6 @@ export default class extends Channel {
 		this.subscriber.on('notesStream', this.onNote);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		if (note.visibility !== 'public') return;
 		if (note.channelId != null) return;
@@ -69,7 +71,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off('notesStream', this.onNote);
diff --git a/packages/backend/src/server/api/stream/channels/hashtag.ts b/packages/backend/src/server/api/stream/channels/hashtag.ts
index 820095dfcf..1b7a58022f 100644
--- a/packages/backend/src/server/api/stream/channels/hashtag.ts
+++ b/packages/backend/src/server/api/stream/channels/hashtag.ts
@@ -1,10 +1,9 @@
-import autobind from 'autobind-decorator';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import Channel from '../channel';
-import { Notes } from '@/models/index';
-import { normalizeForSearch } from '@/misc/normalize-for-search';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { Packed } from '@/misc/schema';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import Channel from '../channel.js';
+import { Notes } from '@/models/index.js';
+import { normalizeForSearch } from '@/misc/normalize-for-search.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'hashtag';
@@ -12,7 +11,11 @@ export default class extends Channel {
 	public static requireCredential = false;
 	private q: string[][];
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		this.q = params.q;
 
@@ -22,7 +25,6 @@ export default class extends Channel {
 		this.subscriber.on('notesStream', this.onNote);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		const noteTags = note.tags ? note.tags.map((t: string) => t.toLowerCase()) : [];
 		const matched = this.q.some(tags => tags.every(tag => noteTags.includes(normalizeForSearch(tag))));
@@ -45,7 +47,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off('notesStream', this.onNote);
diff --git a/packages/backend/src/server/api/stream/channels/home-timeline.ts b/packages/backend/src/server/api/stream/channels/home-timeline.ts
index 445db5c382..3a8e55202a 100644
--- a/packages/backend/src/server/api/stream/channels/home-timeline.ts
+++ b/packages/backend/src/server/api/stream/channels/home-timeline.ts
@@ -1,24 +1,26 @@
-import autobind from 'autobind-decorator';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import Channel from '../channel';
-import { Notes } from '@/models/index';
-import { checkWordMute } from '@/misc/check-word-mute';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { isInstanceMuted } from '@/misc/is-instance-muted';
-import { Packed } from '@/misc/schema';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import Channel from '../channel.js';
+import { Notes } from '@/models/index.js';
+import { checkWordMute } from '@/misc/check-word-mute.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { isInstanceMuted } from '@/misc/is-instance-muted.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'homeTimeline';
 	public static shouldShare = true;
 	public static requireCredential = true;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		// Subscribe events
 		this.subscriber.on('notesStream', this.onNote);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		if (note.channelId) {
 			if (!this.followingChannels.has(note.channelId)) return;
@@ -77,7 +79,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off('notesStream', this.onNote);
diff --git a/packages/backend/src/server/api/stream/channels/hybrid-timeline.ts b/packages/backend/src/server/api/stream/channels/hybrid-timeline.ts
index c0be71fe2d..f3ceeffa1a 100644
--- a/packages/backend/src/server/api/stream/channels/hybrid-timeline.ts
+++ b/packages/backend/src/server/api/stream/channels/hybrid-timeline.ts
@@ -1,19 +1,22 @@
-import autobind from 'autobind-decorator';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import Channel from '../channel';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Notes } from '@/models/index';
-import { checkWordMute } from '@/misc/check-word-mute';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { isInstanceMuted } from '@/misc/is-instance-muted';
-import { Packed } from '@/misc/schema';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import Channel from '../channel.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Notes } from '@/models/index.js';
+import { checkWordMute } from '@/misc/check-word-mute.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { isInstanceMuted } from '@/misc/is-instance-muted.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'hybridTimeline';
 	public static shouldShare = true;
 	public static requireCredential = true;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		const meta = await fetchMeta();
 		if (meta.disableLocalTimeline && !this.user!.isAdmin && !this.user!.isModerator) return;
@@ -22,7 +25,6 @@ export default class extends Channel {
 		this.subscriber.on('notesStream', this.onNote);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		// チャンネルの投稿ではなく、自分自身の投稿 または
 		// チャンネルの投稿ではなく、その投稿のユーザーをフォローしている または
@@ -85,7 +87,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off('notesStream', this.onNote);
diff --git a/packages/backend/src/server/api/stream/channels/index.ts b/packages/backend/src/server/api/stream/channels/index.ts
index f3826c4cf7..d422edde87 100644
--- a/packages/backend/src/server/api/stream/channels/index.ts
+++ b/packages/backend/src/server/api/stream/channels/index.ts
@@ -1,18 +1,18 @@
-import main from './main';
-import homeTimeline from './home-timeline';
-import localTimeline from './local-timeline';
-import hybridTimeline from './hybrid-timeline';
-import globalTimeline from './global-timeline';
-import serverStats from './server-stats';
-import queueStats from './queue-stats';
-import userList from './user-list';
-import antenna from './antenna';
-import messaging from './messaging';
-import messagingIndex from './messaging-index';
-import drive from './drive';
-import hashtag from './hashtag';
-import channel from './channel';
-import admin from './admin';
+import main from './main.js';
+import homeTimeline from './home-timeline.js';
+import localTimeline from './local-timeline.js';
+import hybridTimeline from './hybrid-timeline.js';
+import globalTimeline from './global-timeline.js';
+import serverStats from './server-stats.js';
+import queueStats from './queue-stats.js';
+import userList from './user-list.js';
+import antenna from './antenna.js';
+import messaging from './messaging.js';
+import messagingIndex from './messaging-index.js';
+import drive from './drive.js';
+import hashtag from './hashtag.js';
+import channel from './channel.js';
+import admin from './admin.js';
 
 export default {
 	main,
diff --git a/packages/backend/src/server/api/stream/channels/local-timeline.ts b/packages/backend/src/server/api/stream/channels/local-timeline.ts
index ae8f62ba61..4e198482a0 100644
--- a/packages/backend/src/server/api/stream/channels/local-timeline.ts
+++ b/packages/backend/src/server/api/stream/channels/local-timeline.ts
@@ -1,18 +1,21 @@
-import autobind from 'autobind-decorator';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import Channel from '../channel';
-import { fetchMeta } from '@/misc/fetch-meta';
-import { Notes } from '@/models/index';
-import { checkWordMute } from '@/misc/check-word-mute';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { Packed } from '@/misc/schema';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import Channel from '../channel.js';
+import { fetchMeta } from '@/misc/fetch-meta.js';
+import { Notes } from '@/models/index.js';
+import { checkWordMute } from '@/misc/check-word-mute.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'localTimeline';
 	public static shouldShare = true;
 	public static requireCredential = false;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		const meta = await fetchMeta();
 		if (meta.disableLocalTimeline) {
@@ -23,7 +26,6 @@ export default class extends Channel {
 		this.subscriber.on('notesStream', this.onNote);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		if (note.user.host !== null) return;
 		if (note.visibility !== 'public') return;
@@ -66,7 +68,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off('notesStream', this.onNote);
diff --git a/packages/backend/src/server/api/stream/channels/main.ts b/packages/backend/src/server/api/stream/channels/main.ts
index b41eae7c71..9cfea0bfc4 100644
--- a/packages/backend/src/server/api/stream/channels/main.ts
+++ b/packages/backend/src/server/api/stream/channels/main.ts
@@ -1,14 +1,12 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
-import { Notes } from '@/models/index';
-import { isInstanceMuted, isUserFromMutedInstance } from '@/misc/is-instance-muted';
+import Channel from '../channel.js';
+import { Notes } from '@/models/index.js';
+import { isInstanceMuted, isUserFromMutedInstance } from '@/misc/is-instance-muted.js';
 
 export default class extends Channel {
 	public readonly chName = 'main';
 	public static shouldShare = true;
 	public static requireCredential = true;
 
-	@autobind
 	public async init(params: any) {
 		// Subscribe main stream channel
 		this.subscriber.on(`mainStream:${this.user!.id}`, async data => {
diff --git a/packages/backend/src/server/api/stream/channels/messaging-index.ts b/packages/backend/src/server/api/stream/channels/messaging-index.ts
index 0c495398ab..b930785d20 100644
--- a/packages/backend/src/server/api/stream/channels/messaging-index.ts
+++ b/packages/backend/src/server/api/stream/channels/messaging-index.ts
@@ -1,12 +1,10 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
+import Channel from '../channel.js';
 
 export default class extends Channel {
 	public readonly chName = 'messagingIndex';
 	public static shouldShare = true;
 	public static requireCredential = true;
 
-	@autobind
 	public async init(params: any) {
 		// Subscribe messaging index stream
 		this.subscriber.on(`messagingIndexStream:${this.user!.id}`, data => {
diff --git a/packages/backend/src/server/api/stream/channels/messaging.ts b/packages/backend/src/server/api/stream/channels/messaging.ts
index d8fccf0763..94bbdeca52 100644
--- a/packages/backend/src/server/api/stream/channels/messaging.ts
+++ b/packages/backend/src/server/api/stream/channels/messaging.ts
@@ -1,10 +1,9 @@
-import autobind from 'autobind-decorator';
-import { readUserMessagingMessage, readGroupMessagingMessage, deliverReadActivity } from '../../common/read-messaging-message';
-import Channel from '../channel';
-import { UserGroupJoinings, Users, MessagingMessages } from '@/models/index';
-import { User, ILocalUser, IRemoteUser } from '@/models/entities/user';
-import { UserGroup } from '@/models/entities/user-group';
-import { StreamMessages } from '../types';
+import { readUserMessagingMessage, readGroupMessagingMessage, deliverReadActivity } from '../../common/read-messaging-message.js';
+import Channel from '../channel.js';
+import { UserGroupJoinings, Users, MessagingMessages } from '@/models/index.js';
+import { User, ILocalUser, IRemoteUser } from '@/models/entities/user.js';
+import { UserGroup } from '@/models/entities/user-group.js';
+import { StreamMessages } from '../types.js';
 
 export default class extends Channel {
 	public readonly chName = 'messaging';
@@ -18,7 +17,13 @@ export default class extends Channel {
 	private typers: Record<User['id'], Date> = {};
 	private emitTypersIntervalId: ReturnType<typeof setInterval>;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onEvent = this.onEvent.bind(this);
+		this.onMessage = this.onMessage.bind(this);
+		this.emitTypers = this.emitTypers.bind(this);
+	}
+
 	public async init(params: any) {
 		this.otherpartyId = params.otherparty;
 		this.otherparty = this.otherpartyId ? await Users.findOneOrFail({ id: this.otherpartyId }) : null;
@@ -46,7 +51,6 @@ export default class extends Channel {
 		this.subscriber.on(this.subCh, this.onEvent);
 	}
 
-	@autobind
 	private onEvent(data: StreamMessages['messaging']['payload'] | StreamMessages['groupMessaging']['payload']) {
 		if (data.type === 'typing') {
 			const id = data.body;
@@ -60,7 +64,6 @@ export default class extends Channel {
 		}
 	}
 
-	@autobind
 	public onMessage(type: string, body: any) {
 		switch (type) {
 			case 'read':
@@ -80,7 +83,6 @@ export default class extends Channel {
 		}
 	}
 
-	@autobind
 	private async emitTypers() {
 		const now = new Date();
 
@@ -97,7 +99,6 @@ export default class extends Channel {
 		});
 	}
 
-	@autobind
 	public dispose() {
 		this.subscriber.off(this.subCh, this.onEvent);
 
diff --git a/packages/backend/src/server/api/stream/channels/queue-stats.ts b/packages/backend/src/server/api/stream/channels/queue-stats.ts
index be18438fa3..043d03ab8d 100644
--- a/packages/backend/src/server/api/stream/channels/queue-stats.ts
+++ b/packages/backend/src/server/api/stream/channels/queue-stats.ts
@@ -1,25 +1,27 @@
-import autobind from 'autobind-decorator';
-import Xev from 'xev';
-import Channel from '../channel';
+import { default as Xev } from 'xev';
+import Channel from '../channel.js';
 
-const ev = new Xev();
+const ev = new Xev.default();
 
 export default class extends Channel {
 	public readonly chName = 'queueStats';
 	public static shouldShare = true;
 	public static requireCredential = false;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onStats = this.onStats.bind(this);
+		this.onMessage = this.onMessage.bind(this);
+	}
+
 	public async init(params: any) {
 		ev.addListener('queueStats', this.onStats);
 	}
 
-	@autobind
 	private onStats(stats: any) {
 		this.send('stats', stats);
 	}
 
-	@autobind
 	public onMessage(type: string, body: any) {
 		switch (type) {
 			case 'requestLog':
@@ -34,7 +36,6 @@ export default class extends Channel {
 		}
 	}
 
-	@autobind
 	public dispose() {
 		ev.removeListener('queueStats', this.onStats);
 	}
diff --git a/packages/backend/src/server/api/stream/channels/server-stats.ts b/packages/backend/src/server/api/stream/channels/server-stats.ts
index df89b4c750..0da1895767 100644
--- a/packages/backend/src/server/api/stream/channels/server-stats.ts
+++ b/packages/backend/src/server/api/stream/channels/server-stats.ts
@@ -1,25 +1,27 @@
-import autobind from 'autobind-decorator';
-import Xev from 'xev';
-import Channel from '../channel';
+import { default as Xev } from 'xev';
+import Channel from '../channel.js';
 
-const ev = new Xev();
+const ev = new Xev.default();
 
 export default class extends Channel {
 	public readonly chName = 'serverStats';
 	public static shouldShare = true;
 	public static requireCredential = false;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.onStats = this.onStats.bind(this);
+		this.onMessage = this.onMessage.bind(this);
+	}
+
 	public async init(params: any) {
 		ev.addListener('serverStats', this.onStats);
 	}
 
-	@autobind
 	private onStats(stats: any) {
 		this.send('stats', stats);
 	}
 
-	@autobind
 	public onMessage(type: string, body: any) {
 		switch (type) {
 			case 'requestLog':
@@ -34,7 +36,6 @@ export default class extends Channel {
 		}
 	}
 
-	@autobind
 	public dispose() {
 		ev.removeListener('serverStats', this.onStats);
 	}
diff --git a/packages/backend/src/server/api/stream/channels/user-list.ts b/packages/backend/src/server/api/stream/channels/user-list.ts
index b75920a180..57523c8488 100644
--- a/packages/backend/src/server/api/stream/channels/user-list.ts
+++ b/packages/backend/src/server/api/stream/channels/user-list.ts
@@ -1,10 +1,9 @@
-import autobind from 'autobind-decorator';
-import Channel from '../channel';
-import { Notes, UserListJoinings, UserLists } from '@/models/index';
-import { isMutedUserRelated } from '@/misc/is-muted-user-related';
-import { User } from '@/models/entities/user';
-import { isBlockerUserRelated } from '@/misc/is-blocker-user-related';
-import { Packed } from '@/misc/schema';
+import Channel from '../channel.js';
+import { Notes, UserListJoinings, UserLists } from '@/models/index.js';
+import { isMutedUserRelated } from '@/misc/is-muted-user-related.js';
+import { User } from '@/models/entities/user.js';
+import { isBlockerUserRelated } from '@/misc/is-blocker-user-related.js';
+import { Packed } from '@/misc/schema.js';
 
 export default class extends Channel {
 	public readonly chName = 'userList';
@@ -14,7 +13,12 @@ export default class extends Channel {
 	public listUsers: User['id'][] = [];
 	private listUsersClock: NodeJS.Timer;
 
-	@autobind
+	constructor(id: string, connection: Channel['connection']) {
+		super(id, connection);
+		this.updateListUsers = this.updateListUsers.bind(this);
+		this.onNote = this.onNote.bind(this);
+	}
+
 	public async init(params: any) {
 		this.listId = params.listId as string;
 
@@ -34,7 +38,6 @@ export default class extends Channel {
 		this.listUsersClock = setInterval(this.updateListUsers, 5000);
 	}
 
-	@autobind
 	private async updateListUsers() {
 		const users = await UserListJoinings.find({
 			where: {
@@ -46,7 +49,6 @@ export default class extends Channel {
 		this.listUsers = users.map(x => x.userId);
 	}
 
-	@autobind
 	private async onNote(note: Packed<'Note'>) {
 		if (!this.listUsers.includes(note.userId)) return;
 
@@ -81,7 +83,6 @@ export default class extends Channel {
 		this.send('note', note);
 	}
 
-	@autobind
 	public dispose() {
 		// Unsubscribe events
 		this.subscriber.off(`userListStream:${this.listId}`, this.send);
diff --git a/packages/backend/src/server/api/stream/index.ts b/packages/backend/src/server/api/stream/index.ts
index 84689bca1a..0cb38e2a99 100644
--- a/packages/backend/src/server/api/stream/index.ts
+++ b/packages/backend/src/server/api/stream/index.ts
@@ -1,21 +1,20 @@
-import autobind from 'autobind-decorator';
 import * as websocket from 'websocket';
-import { readNotification } from '../common/read-notification';
-import call from '../call';
-import readNote from '@/services/note/read';
-import Channel from './channel';
-import channels from './channels/index';
+import { readNotification } from '../common/read-notification.js';
+import call from '../call.js';
+import readNote from '@/services/note/read.js';
+import Channel from './channel.js';
+import channels from './channels/index.js';
 import { EventEmitter } from 'events';
-import { User } from '@/models/entities/user';
-import { Channel as ChannelModel } from '@/models/entities/channel';
-import { Users, Followings, Mutings, UserProfiles, ChannelFollowings, Blockings } from '@/models/index';
-import { ApiError } from '../error';
-import { AccessToken } from '@/models/entities/access-token';
-import { UserProfile } from '@/models/entities/user-profile';
-import { publishChannelStream, publishGroupMessagingStream, publishMessagingStream } from '@/services/stream';
-import { UserGroup } from '@/models/entities/user-group';
-import { StreamEventEmitter, StreamMessages } from './types';
-import { Packed } from '@/misc/schema';
+import { User } from '@/models/entities/user.js';
+import { Channel as ChannelModel } from '@/models/entities/channel.js';
+import { Users, Followings, Mutings, UserProfiles, ChannelFollowings, Blockings } from '@/models/index.js';
+import { ApiError } from '../error.js';
+import { AccessToken } from '@/models/entities/access-token.js';
+import { UserProfile } from '@/models/entities/user-profile.js';
+import { publishChannelStream, publishGroupMessagingStream, publishMessagingStream } from '@/services/stream.js';
+import { UserGroup } from '@/models/entities/user-group.js';
+import { StreamEventEmitter, StreamMessages } from './types.js';
+import { Packed } from '@/misc/schema.js';
 
 /**
  * Main stream connection
@@ -38,13 +37,18 @@ export default class Connection {
 		wsConnection: websocket.connection,
 		subscriber: EventEmitter,
 		user: User | null | undefined,
-		token: AccessToken | null | undefined
+		token: AccessToken | null | undefined,
 	) {
 		this.wsConnection = wsConnection;
 		this.subscriber = subscriber;
 		if (user) this.user = user;
 		if (token) this.token = token;
 
+		this.onWsConnectionMessage = this.onWsConnectionMessage.bind(this);
+		this.onUserEvent = this.onUserEvent.bind(this);
+		this.onNoteStreamMessage = this.onNoteStreamMessage.bind(this);
+		this.onBroadcastMessage = this.onBroadcastMessage.bind(this);
+
 		this.wsConnection.on('message', this.onWsConnectionMessage);
 
 		this.subscriber.on('broadcast', data => {
@@ -62,7 +66,6 @@ export default class Connection {
 		}
 	}
 
-	@autobind
 	private onUserEvent(data: StreamMessages['user']['payload']) { // { type, body }と展開するとそれぞれ型が分離してしまう
 		switch (data.type) {
 			case 'follow':
@@ -108,8 +111,8 @@ export default class Connection {
 	/**
 	 * クライアントからメッセージ受信時
 	 */
-	@autobind
-	private async onWsConnectionMessage(data: websocket.IMessage) {
+	private async onWsConnectionMessage(data: websocket.Message) {
+		if (data.type !== 'utf8') return;
 		if (data.utf8Data == null) return;
 
 		let obj: Record<string, any>;
@@ -143,12 +146,10 @@ export default class Connection {
 		}
 	}
 
-	@autobind
 	private onBroadcastMessage(data: StreamMessages['broadcast']['payload']) {
 		this.sendMessageToWs(data.type, data.body);
 	}
 
-	@autobind
 	public cacheNote(note: Packed<'Note'>) {
 		const add = (note: Packed<'Note'>) => {
 			const existIndex = this.cachedNotes.findIndex(n => n.id === note.id);
@@ -168,7 +169,6 @@ export default class Connection {
 		if (note.renote) add(note.renote);
 	}
 
-	@autobind
 	private readNote(body: any) {
 		const id = body.id;
 
@@ -186,7 +186,6 @@ export default class Connection {
 	/**
 	 * APIリクエスト要求時
 	 */
-	@autobind
 	private async onApiRequest(payload: any) {
 		// 新鮮なデータを利用するためにユーザーをフェッチ
 		const user = this.user ? await Users.findOne(this.user.id) : null;
@@ -209,7 +208,6 @@ export default class Connection {
 		});
 	}
 
-	@autobind
 	private onReadNotification(payload: any) {
 		if (!payload.id) return;
 		readNotification(this.user!.id, [payload.id]);
@@ -218,7 +216,6 @@ export default class Connection {
 	/**
 	 * 投稿購読要求時
 	 */
-	@autobind
 	private onSubscribeNote(payload: any) {
 		if (!payload.id) return;
 
@@ -236,7 +233,6 @@ export default class Connection {
 	/**
 	 * 投稿購読解除要求時
 	 */
-	@autobind
 	private onUnsubscribeNote(payload: any) {
 		if (!payload.id) return;
 
@@ -247,7 +243,6 @@ export default class Connection {
 		}
 	}
 
-	@autobind
 	private async onNoteStreamMessage(data: StreamMessages['note']['payload']) {
 		this.sendMessageToWs('noteUpdated', {
 			id: data.body.id,
@@ -259,7 +254,6 @@ export default class Connection {
 	/**
 	 * チャンネル接続要求時
 	 */
-	@autobind
 	private onChannelConnectRequested(payload: any) {
 		const { channel, id, params, pong } = payload;
 		this.connectChannel(id, params, channel, pong);
@@ -268,7 +262,6 @@ export default class Connection {
 	/**
 	 * チャンネル切断要求時
 	 */
-	@autobind
 	private onChannelDisconnectRequested(payload: any) {
 		const { id } = payload;
 		this.disconnectChannel(id);
@@ -277,7 +270,6 @@ export default class Connection {
 	/**
 	 * クライアントにメッセージ送信
 	 */
-	@autobind
 	public sendMessageToWs(type: string, payload: any) {
 		this.wsConnection.send(JSON.stringify({
 			type: type,
@@ -288,7 +280,6 @@ export default class Connection {
 	/**
 	 * チャンネルに接続
 	 */
-	@autobind
 	public connectChannel(id: string, params: any, channel: string, pong = false) {
 		if ((channels as any)[channel].requireCredential && this.user == null) {
 			return;
@@ -314,7 +305,6 @@ export default class Connection {
 	 * チャンネルから切断
 	 * @param id チャンネルコネクションID
 	 */
-	@autobind
 	public disconnectChannel(id: string) {
 		const channel = this.channels.find(c => c.id === id);
 
@@ -328,7 +318,6 @@ export default class Connection {
 	 * チャンネルへメッセージ送信要求時
 	 * @param data メッセージ
 	 */
-	@autobind
 	private onChannelMessageRequested(data: any) {
 		const channel = this.channels.find(c => c.id === data.id);
 		if (channel != null && channel.onMessage != null) {
@@ -336,14 +325,12 @@ export default class Connection {
 		}
 	}
 
-	@autobind
 	private typingOnChannel(channel: ChannelModel['id']) {
 		if (this.user) {
 			publishChannelStream(channel, 'typing', this.user.id);
 		}
 	}
 
-	@autobind
 	private typingOnMessaging(param: { partner?: User['id']; group?: UserGroup['id']; }) {
 		if (this.user) {
 			if (param.partner) {
@@ -354,7 +341,6 @@ export default class Connection {
 		}
 	}
 
-	@autobind
 	private async updateFollowing() {
 		const followings = await Followings.find({
 			where: {
@@ -366,7 +352,6 @@ export default class Connection {
 		this.following = new Set<string>(followings.map(x => x.followeeId));
 	}
 
-	@autobind
 	private async updateMuting() {
 		const mutings = await Mutings.find({
 			where: {
@@ -378,7 +363,6 @@ export default class Connection {
 		this.muting = new Set<string>(mutings.map(x => x.muteeId));
 	}
 
-	@autobind
 	private async updateBlocking() { // ここでいうBlockingは被Blockingの意
 		const blockings = await Blockings.find({
 			where: {
@@ -390,7 +374,6 @@ export default class Connection {
 		this.blocking = new Set<string>(blockings.map(x => x.blockerId));
 	}
 
-	@autobind
 	private async updateFollowingChannels() {
 		const followings = await ChannelFollowings.find({
 			where: {
@@ -402,7 +385,6 @@ export default class Connection {
 		this.followingChannels = new Set<string>(followings.map(x => x.followeeId));
 	}
 
-	@autobind
 	private async updateUserProfile() {
 		this.userProfile = await UserProfiles.findOne({
 			userId: this.user!.id,
@@ -412,7 +394,6 @@ export default class Connection {
 	/**
 	 * ストリームが切れたとき
 	 */
-	@autobind
 	public dispose() {
 		for (const c of this.channels.filter(c => c.dispose)) {
 			if (c.dispose) c.dispose();
diff --git a/packages/backend/src/server/api/stream/types.ts b/packages/backend/src/server/api/stream/types.ts
index e2f1c6fc9c..90cf59038d 100644
--- a/packages/backend/src/server/api/stream/types.ts
+++ b/packages/backend/src/server/api/stream/types.ts
@@ -1,20 +1,20 @@
 import { EventEmitter } from 'events';
 import Emitter from 'strict-event-emitter-types';
-import { Channel } from '@/models/entities/channel';
-import { User } from '@/models/entities/user';
-import { UserProfile } from '@/models/entities/user-profile';
-import { Note } from '@/models/entities/note';
-import { Antenna } from '@/models/entities/antenna';
-import { DriveFile } from '@/models/entities/drive-file';
-import { DriveFolder } from '@/models/entities/drive-folder';
-import { Emoji } from '@/models/entities/emoji';
-import { UserList } from '@/models/entities/user-list';
-import { MessagingMessage } from '@/models/entities/messaging-message';
-import { UserGroup } from '@/models/entities/user-group';
-import { AbuseUserReport } from '@/models/entities/abuse-user-report';
-import { Signin } from '@/models/entities/signin';
-import { Page } from '@/models/entities/page';
-import { Packed } from '@/misc/schema';
+import { Channel } from '@/models/entities/channel.js';
+import { User } from '@/models/entities/user.js';
+import { UserProfile } from '@/models/entities/user-profile.js';
+import { Note } from '@/models/entities/note.js';
+import { Antenna } from '@/models/entities/antenna.js';
+import { DriveFile } from '@/models/entities/drive-file.js';
+import { DriveFolder } from '@/models/entities/drive-folder.js';
+import { Emoji } from '@/models/entities/emoji.js';
+import { UserList } from '@/models/entities/user-list.js';
+import { MessagingMessage } from '@/models/entities/messaging-message.js';
+import { UserGroup } from '@/models/entities/user-group.js';
+import { AbuseUserReport } from '@/models/entities/abuse-user-report.js';
+import { Signin } from '@/models/entities/signin.js';
+import { Page } from '@/models/entities/page.js';
+import { Packed } from '@/misc/schema.js';
 
 //#region Stream type-body definitions
 export interface InternalStreamTypes {
@@ -84,6 +84,7 @@ export interface MainStreamTypes {
 	};
 	driveFileCreated: Packed<'DriveFile'>;
 	readAntenna: Antenna;
+	receiveFollowRequest: Packed<'User'>;
 }
 
 export interface DriveStreamTypes {
diff --git a/packages/backend/src/server/api/streaming.ts b/packages/backend/src/server/api/streaming.ts
index b706b1b8df..2a34edac67 100644
--- a/packages/backend/src/server/api/streaming.ts
+++ b/packages/backend/src/server/api/streaming.ts
@@ -1,14 +1,14 @@
 import * as http from 'http';
 import * as websocket from 'websocket';
 
-import MainStreamConnection from './stream/index';
+import MainStreamConnection from './stream/index.js';
 import { ParsedUrlQuery } from 'querystring';
-import authenticate from './authenticate';
+import authenticate from './authenticate.js';
 import { EventEmitter } from 'events';
-import { subsdcriber as redisClient } from '../../db/redis';
-import { Users } from '@/models/index';
+import { subsdcriber as redisClient } from '../../db/redis.js';
+import { Users } from '@/models/index.js';
 
-module.exports = (server: http.Server) => {
+export const initializeStreamingServer = (server: http.Server) => {
 	// Init websocket server
 	const ws = new websocket.server({
 		httpServer: server,